The Bell X-1 was the first crewed airplane to exceed the speed of sound in level flight and was the first of the X-planes.
XS-1 pilots
{| class="wikitable"
! width="125" |Pilot
! width="100" |Agency
! width="50" |Flights
! width="175" |Aircraft
|-
| Joseph Cannon
| Bell Aircraft
| 1
| 46-064
|-
| Chalmers "Slick" Goodlin
| Bell Aircraft
| 26
| 46-062 (9), 46-063 (17)
|-
| Alvin "Tex" Johnston
| Bell Aircraft
| 1
| 46-063
|-
| Jack Woolams
| Bell Aircraft
| 10
| 46-062
|-
| Robert Champine
| NACA
| 13
| 46-063
|-
| Scott Crossfield
| NACA
| 10
| 46-063
|-
| John H. Griffith
| NACA
| 9
| 46-063
|-
| Herb Hoover
| NACA
| 14
| 46-063
|-
| Howard Lilly
| NACA
| 6
| 46-063
|-
| Joseph A. Walker
| NACA
| 2
| 46-063
|-
| Fred Ascani
| USAF
| 1
| 46-063
|-
| Albert Boyd
| USAF
| 1
| 46-062
|-
| Frank Everest
| USAF
| 10
| 46-062
|-
| James Fitzgerald
| USAF
| 7
| 46-062
|-
| Patrick Fleming
| USAF
| 1
| 46-062
|-
| Richard Johnson
| USAF
| 1
| 46-062
|-
| Gustav Lundquist
| USAF
| 6
| 46-062
|-
| Jack Ridley
| USAF
| 5
| 46-062
|-
| Chuck Yeager
| USAF
| 34
| 46-062 (33), 46-063 (1)
|}
XS-1 flights
{| class="wikitable"
! width="65" |Vehicle<br>Flight #
! width="120" |Date
! width="125" |Pilot
! width="50" |Aircraft
! width="65" |Agency
! width="50" |Velocity<br>-Mach-
! width="50" |Altitude<br>- m -
! width="175" |Comments
|-
| XS-1 #1
| January 19, 1946
| Jack Woolams
| 46-062
| Bell 1 #1
| ?
| ?
| Pinecastle AAF Base, FL. Glide flight.
|-
| XS-1 #2
| February 5, 1946
| Jack Woolams
| 46-062
| Bell 2 #1
| ?
| ?
| Pinecastle AAF Base, FL. Glide flight.
|-
| XS-1 #3
| February 5, 1946
| Jack Woolams
| 46-062
| Bell 3 #1
| ?
| ?
| Pinecastle AAF Base, FL. 2nd flight on this date. Glide flight.
|-
| XS-1 #4
| February 11, 1946
| Jack Woolams
| 46-062
| Bell 4 #1
| ?
| ?
| Pinecastle AAF Base, FL. Gear retracts after landing, left wing damage. Glide flight.
|-
| XS-1 #5
| February 19, 1946
| Jack Woolams
| 46-062
| Bell 5 #1
| ?
| ?
| Pinecastle AAF Base, FL. Nose Gear retracted on landing. Landing gear door damage. Glide flight.
|-
| XS-1 #6
| February 25, 1946
| Jack Woolams
| 46-062
| Bell 6 #1
| ?
| ?
| Pinecastle AAF Base, FL<br>Directional stability tests. Glide flight.
|-
| XS-1 #7
| February 25, 1946
| Jack Woolams
| 46-062
| Bell 7 #1
| ?
| ?
| Pinecastle AAF Base, FL. Longitudinal stability tests. 2nd flight on this date. Glide flight.
|-
| XS-1 #8
| February 26, 1946
| Jack Woolams
| 46-062
| Bell 8 #1
| ?
| ?
| Pinecastle AAF Base, FL. Dynamic stability tests. Glide flight.
|-
| XS-1 #9
| February 26, 1946
| Jack Woolams
| 46-062
| Bell 9 #1
| ?
| ?
| Pinecastle AAF Base, FL. Roll rate tests. 2nd flight on this date. Glide flight.
|-
| XS-1 #10
| March 6, 1946
| Jack Woolams
| 46-062
| Bell 10 #1
| ?
| ?
| Pinecastle AAF Base, FL. Longitudinal stability tests. Glide flight.
|-
| XS-1 #11
| October 11, 1946
| Chalmers Goodlin
| 46-063
| Bell 1 #2
| ?
| ?
| All XS-1 flights now from Muroc AAF Base, CA. Glide flight, familiarization.
|-
| XS-1 #12
| October 14, 1946
| Chalmers Goodlin
| 46-063
| Bell 2 #2
| ?
| ?
| Glide flight.
|-
| XS-1 #13
| October 17, 1946
| Chalmers Goodlin
| 46-063
| Bell 3 #2
| ?
| ?
| Glide flight.
|-
| XS-1 #14
| December 2, 1946
| Chalmers Goodlin
| 46-063
| Bell 4 #2
| ?
| ?
| Glide flight. Check fuel jettison system.
|-
| XS-1 #15
| December 9, 1946
| Chalmers Goodlin
| 46-063
| Bell 5 #2
| 0.79
| 10,675
| First powered flight. Minor engine fire.
|-
| XS-1 #16
| December 20, 1946
| Chalmers Goodlin
| 46-063
| Bell 6 #2
| ?
| ?
| Familiarization flight. Powered.
|-
| XS-1 #17
| January 8, 1947
| Chalmers Goodlin
| 46-063
| Bell 7 #2
| 0.80
| 10,675
| Buffet boundary investigation.
|-
| XS-1 #18
| January 17, 1947
| Chalmers Goodlin
| 46-063
| Bell 8 #2
| 0.80
| ?
| Buffet boundary investigation. Full power climb.
|-
| XS-1 #19
| January 22, 1947
| Chalmers Goodlin
| 46-063
| Bell 9 #2
| ?
| ?
| Buffet boundary investigation. Full power climb. Telemetry failed.
|-
| XS-1 #20
| January 23, 1947
| Chalmers Goodlin
| 46-063
| Bell 10 #2
| ?
| ?
| Buffet boundary investigation. Full power climb.
|-
| XS-1 #21
| January 30, 1947
| Chalmers Goodlin
| 46-063
| Bell 11 #2
| 0.75
| ?
| Accelerated stalls. Partial power.
|-
| XS-1 #22
| January 31, 1947
| Chalmers Goodlin
| 46-063
| Bell 12 #2
| 0.70
| ?
| Buffet boundary investigation.
|-
| XS-1 #23
| February 5, 1947
| Chalmers Goodlin
| 46-063
| Bell 13 #2
| ?
| ?
| Machmeter calibration.
|-
| XS-1 #24
| February 7, 1947
| Chalmers Goodlin
| 46-063
| Bell 14 #2
| ?
| ?
| Buffet boundary investigation.
|-
| XS-1 #25
| February 19, 1947
| Chalmers Goodlin
| 46-063
| Bell 15 #2
| ?
| ?
| Accelerated stalls.
|-
| XS-1 #26
| February 21, 1947
| Chalmers Goodlin
| 46-063
| Bell 16 #2
| ?
| ?
| Aborted after launch. Low engine-chamber pressure.
|-
| XS-1 #27
| April 10, 1947
| Chalmers Goodlin
| 46-062
| Bell 11 #1
| ?
| ?
| Glide flight, stall check.
|-
| XS-1 #28
| April 11, 1947
| Chalmers Goodlin
| 46-062
| Bell 12 #1
| ?
| ?
| First powered flight of aircraft #1. Nosewheel damaged.
|-
| XS-1 #29
| April 29, 1947
| Chalmers Goodlin
| 46-062
| Bell 13 #1
| ?
| ?
| Handling qualities check.
|-
| XS-1 #30
| April 30, 1947
| Chalmers Goodlin
| 46-062
| Bell 14 #1
| ?
| ?
| Handling qualities check.
|-
| XS-1 #31
| May 5, 1947
| Chalmers Goodlin
| 46-062
| Bell 15 #1
| ?
| ?
| Handling qualities check.
|-
| XS-1 #32
| May 15, 1947
| Chalmers Goodlin
| 46-062
| Bell 16 #1
| ?
| ?
| Buffet boundary test. Aileron damper malfunction.
|-
| XS-1 #33
| May 19, 1947
| Chalmers Goodlin
| 46-062
| Bell 17 #1
| ?
| ?
| Buffet boundary test.
|-
| XS-1 #34
| May 21, 1947
| Chalmers Goodlin
| 46-062
| Bell 18 #1
| ?
| ?
| Buffet boundary test.
|-
| XS-1 #35
| May 22, 1947
| Alvin "Tex" Johnston
| 46-063
| Bell 17 #2
| 0.72
| ?
| Pilot familiarization. 8 g (78 m/s²) pullout.
|-
| XS-1 #36
| May 29, 1947
| Chalmers Goodlin
| 46-063
| Bell 18 #2
| 0.72
| ?
| Airspeed calibration. End of Bell contractor program.
|-
| XS-1 #37
| June 5, 1947
| Chalmers Goodlin
| 46-062
| Bell 19 #1
| ?
| ?
| Demonstration for Aviation Writers Association.
|-
| XS-1 #38
| August 6, 1947
| Chuck Yeager
| 46-062
| USAF glide 1
| ?
| ?
| Pilot familiarization.
|-
| XS-1 #39
| August 7, 1947
| Chuck Yeager
| 46-062
| USAF glide 2
| ?
| ?
| Glide flight.
|-
| XS-1 #40
| August 8, 1947
| Chuck Yeager
| 46-062
| USAF glide 3
| ?
| ?
| Glide flight.
|-
| XS-1 #41
| August 29, 1947
| Chuck Yeager
| 46-062
| USAF powered 1
| 0.85
| ?
| First USAF powered flight.
|-
| XS-1 #42
| September 4, 1947
| Chuck Yeager
| 46-062
| USAF 2
| 0.89
| ?
| Telemetry failure. Flight had to be repeated.
|-
| XS-1 #43
| September 8, 1947
| Chuck Yeager
| 46-062
| USAF 3
| ?
| ?
| -
|-
| XS-1 #44
| September 10, 1947
| Chuck Yeager
| 46-062
| USAF 4
| 0.91
| ?
| Stability and control test.
|-
| XS-1 #45
| September 12, 1947
| Chuck Yeager
| 46-062
| USAF 5
| 0.92
| ?
| Check elevator, stabilizer and buffet.
|-
| XS-1 #46
| September 25, 1947
| Chuck Yeager
| 46-063
| NACA acceptance
| ?
| ?
| Number 4 engine tube burned out.
|-
| XS-1 #47
| October 3, 1947
| Chuck Yeager
| 46-062
| USAF 6
| ?
| ?
| Check elevator, stabilizer and buffet.
|-
| XS-1 #48
| October 8, 1947
| Chuck Yeager
| 46-062
| USAF 7
| 0.925
| ?
| Airspeed calibration flight.
|-
| XS-1 #49
| October 10, 1947
| Chuck Yeager
| 46-062
| USAF 8
| 0.997
| ?
| Stability and control test.
|-
| XS-1 #50
| October 14, 1947
| Chuck Yeager
| 46-062
| USAF 9
| 1.06
| 13,115
| First supersonic flight. 1,126 km/h.
|-
| XS-1 #51
| October 21, 1947
| Herb Hoover
| 46-063
| NACA glide 1
| ?
| ?
| Familiarization flight. Stall check. Nose wheel collapsed at landing.
|-
| XS-1 #52
| October 27, 1947
| Chuck Yeager
| 46-062
| USAF 10
| ?
| ?
| Power failure. Rocket didn't fire.
|-
| XS-1 #53
| October 28, 1947
| Chuck Yeager
| 46-062
| USAF 11
| ?
| ?
| Telemetry failure.
|-
| XS-1 #54
| October 29, 1947
| Chuck Yeager
| 46-062
| USAF 12
| ?
| ?
| Telemetry failure.
|-
| XS-1 #55
| October 31, 1947
| Chuck Yeager
| 46-062
| USAF 13
| ?
| ?
| -
|-
| XS-1 #56
| November 3, 1947
| Chuck Yeager
| 46-062
| USAF 14
| ?
| ?
| -
|-
| XS-1 #57
| November 4, 1947
| Chuck Yeager
| 46-062
| USAF 15
| ?
| ?
| -
|-
| XS-1 #58
| November 6, 1947
| Chuck Yeager
| 46-062
| USAF 16
| 1.35
| 14,823
| First-ever aircraft flight to exceed July 6, 1944, flight speed record (702 mph/1,130 km/h) of Heinz Dittmar in Me 163B V18 prototype
|-
| XS-1 #59
| December 16, 1947
| Herb Hoover
| 46-063
| NACA powered 1
| 0.84
| ?
| No record of telemetry.
|-
| XS-1 #60
| December 17, 1947
| Herb Hoover
| 46-063
| NACA 2
| 0.80
| ?
| Familiarization.
|-
| XS-1 #61
| January 6, 1948
| Herb Hoover
| 46-063
| NACA 3
| 0.74
| ?
| Turns, pull-ups to buffet.
|-
| XS-1 #62
| January 8, 1948
| Herb Hoover
| 46-063
| NACA 4
| 0.83
| ?
| Turns, pull-ups to buffet.
|-
| XS-1 #63
| January 9, 1948
| Howard Lilly
| 46-063
| NACA 5
| ?
| ?
| Pilot familiarization.
|-
| XS-1 #64
| January 15, 1948
| Howard Lilly
| 46-063
| NACA 6
| 0.76
| ?
| Turns, pull-ups to buffet. Sideslips.
|-
| XS-1 #65
| January 16, 1948
| Chuck Yeager
| 46-062
| USAF 17
| 0.9
| ?
| Airspeed calibration.
|-
| XS-1 #66
| January 21, 1948
| Herb Hoover
| 46-063
| NACA 7
| 0.82
| 8,845
| Stabilizer effectiveness test.
|-
| XS-1 #67
| January 22, 1948
| Chuck Yeager
| 46-062
| USAF 18
| 1.2
| ?
| Pressure distribution survey.
|-
| XS-1 #68
| January 23, 1948
| Herb Hoover
| 46-063
| NACA 8
| 0.83
| ?
| Attempted high speed flight. Aborted due to drop in chamber pressure.
|-
| XS-1 #69
| January 27, 1948
| Herb Hoover
| 46-063
| NACA 9
| 0.925
| 11,590
| High speed flight. Cylinders 2 and 3 didn't fire.
|-
| XS-1 #70
| January 30, 1948
| Chuck Yeager
| 46-062
| USAF 19
| 1.1
| ?
| Pressure distribution survey.
|-
| XS-1 #71
| February 28, 1948
| James Fitzgerald
| 46-062
| USAF 20
| ?
| ?
| Engine fire at launch. Propellants jettisoned. Glide flight.
|-
| XS-1 #72
| March 4, 1948
| Herb Hoover
| 46-063
| NACA 10
| 0.943
| 12,200
| High speed flight.
|-
| XS-1 #73
| March 10, 1948
| Herb Hoover
| 46-063
| NACA 11
| 1.065
| ?
| First NACA supersonic flight. Nose wheel didn't extend at landing. Minor damage.
|-
| XS-1 #74
| March 11, 1948
| Chuck Yeager
| 46-062
| USAF 21
| 1.25
| ?
| Reached Mach 1.25 in a dive.
|-
| XS-1 #75
| March 22, 1948
| Herb Hoover
| 46-063
| NACA 12
| 1.12
| ?
| Stability and loads test.
|-
| XS-1 #76
| March 26, 1948
| Chuck Yeager
| 46-062
| USAF 22
| 1.45
| 12,239
| Reached Mach 1.45 in a dive. Highest speed achieved in original XS-1.
|-
| XS-1 #77
| March 30, 1948
| Herb Hoover
| 46-063
| NACA 13
| 0.90
| ?
| Stability and loads test.
|-
| XS-1 #78
| March 31, 1948
| Howard Lilly
| 46-063
| NACA 14
| 1.10
| ?
| Stability and loads test.
|-
| XS-1 #79
| March 31, 1948
| Chuck Yeager
| 46-062
| USAF 23
| ?
| ?
| Engine shutdown after launch. Propellants jettisoned. Glide flight.
|-
| XS-1 #80
| April 5, 1948
| Howard Lilly
| 46-063
| NACA 15
| ?
| ?
| Engine didn't ignite. Propellants jettisoned. Glide flight.
|-
| XS-1 #81
| April 6, 1948
| James Fitzgerald
| 46-062
| USAF 24
| 1.1
| 12,505
| Pilot check flight. All 4 cylinders fired.
|-
| XS-1 #82
| April 7, 1948
| Gustav Lundquist
| 46-062
| USAF 25
| ?
| ?
| Glide flight.
|-
| XS-1 #83
| April 8, 1948
| James Fitzgerald
| 46-062
| USAF 26
| ?
| ?
| Familiarization flight.
|-
| XS-1 #84
| April 9, 1948
| Howard Lilly
| 46-063
| NACA 16
| 0.89
| ?
| Stability and loads test.
|-
| XS-1 #85
| April 9, 1948
| Gustav Lundquist
| 46-062
| USAF 27
| ?
| ?
| Powered pilot-check flight.
|-
| XS-1 #86
| April 16, 1948
| Howard Lilly
| 46-063
| NACA 17
| ?
| ?
| Stability and loads test. Nose wheel collapsed on landing causing moderate damage.
|-
| XS-1 #87
| April 16, 1948
| Gustav Lundquist
| 46-062
| USAF 28
| ?
| ?
| Pressure distribution test. Only cylinders 2 and 4 fired.
|-
| XS-1 #88
| April 26, 1948
| James Fitzgerald
| 46-062
| USAF 29
| 0.9
| ?
| Aborted due to rocket malfunction.
|-
| XS-1 #89
| April 29, 1948
| Gustav Lundquist
| 46-062
| USAF 30
| 1.18
| ?
| Pressure distribution test.
|-
| XS-1 #90
| May 4, 1948
| James Fitzgerald
| 46-062
| USAF 31
| 1.15
| ?
| Pressure distribution test.
|-
| XS-1 #91
| May 21, 1948
| Gustav Lundquist
| 46-062
| USAF 32
| 0.92
| ?
| Stability, control and buffeting test.
|-
| XS-1 #92
| May 25, 1948
| James Fitzgerald
| 46-062
| USAF 33
| 1.08
| ?
| Wing, tail loads, buffet test.
|-
| XS-1 #93
| May 26, 1948
| Chuck Yeager
| 46-062
| USAF 34
| 1.05
| ?
| Wing, tail loads, buffet test.
|-
| XS-1 #94
| June 3, 1948
| Gustav Lundquist
| 46-062
| USAF 35
| ?
| ?
| Left main landing gear door opened in flight. Nose wheel collapsed on landing.
|-
| XS-1 #95
| November 1, 1948
| Herb Hoover
| 46-063
| NACA 18
| 0.9
| ?
| Stability and control test. Number 4 cylinder did not fire.
|-
| XS-1 #96
| November 15, 1948
| Herb Hoover
| 46-063
| NACA 19
| 0.98
| ?
| Stability, control and pressure distribution test.
|-
| XS-1 #97
| November 23, 1948
| Robert Champine
| 46-063
| NACA 20
| ?
| ?
| Pilot familiarization. Handling qualities and pressure distribution test.
|-
| XS-1 #98
| November 29, 1948
| Robert Champine
| 46-063
| NACA 21
| 0.88
| ?
| Handling qualities and pressure distribution test.
|-
| XS-1 #99
| November 30, 1948
| Robert Champine
| 46-063
| NACA 22
| ?
| ?
| Handling qualities and pressure distribution test.
|-
| XS-1 #100
| December 1, 1948
| Chuck Yeager
| 46-062
| USAF 36
| 1.0
| ?
| Wing, tail loads and handling qualities at mach 1.
|-
| XS-1 #101
| December 2, 1948
| Robert Champine
| 46-063
| NACA 23
| 1.0
| ?
| Handling qualities and pressure distribution test.
|-
| XS-1 #102
| December 13, 1948
| Chuck Yeager
| 46-062
| USAF 37
| 1.0
| ?
| Wing, tail loads and handling qualities at mach 1.
|-
| XS-1 #103
| December 23, 1948
| Chuck Yeager
| 46-062
| USAF 38
| 1.09
| ?
| Wing, tail loads during supersonic flight at high altitude.
|-
| XS-1 #104
| January 5, 1949
| Chuck Yeager
| 46-062
| USAF 39
| 1.03
| 23,000