St. Thomas Municipal Airport located east of St. Thomas, Ontario, Canada is a small airport serving the general aviation needs of the area. It was established in 1941 as an air training base for the British Commonwealth Air Training Program. The base was operated by the Department of National Defence until the late 1940s as a relief field for No. 14 Service Flying Training School Aylmer, Ontario and No. 4 Bombing & Gunnery School Fingal, Ontario. It has three runways, and four IFR approaches.
thumbnail|left|Map of the airport
The airport is classified as an airport of entry by Nav Canada and is staffed by the Canada Border Services Agency (CBSA) on a call-out basis from the London International Airport. CBSA officers at this airport can handle general aviation aircraft only, with no more than 15 passengers.
Runway 15/33 has been listed as closed since at least August 2017. The current NOTAM indicates that it was supposed to reopen in August 2020.
Historical aerodrome information
In approximately 1942 the aerodrome was listed as "RCAF Aerodrome - St. Thomas, Ontario" at with a variation of 5 degrees west and elevation of . The field was listed as "all hard surfaced" and had three runways listed as follows:
{| class="wikitable"
|-
! Runway name
! Length
! Width
! Surface
|-
| 15/33
|
|
| Hard surfaced
|-
| 9/27
|
|
| Hard surfaced
|-
| 3/21
|
|
| Hard surfaced
|}
BCATP buildings from 1941
<gallery>
File:RCAF St. Thomas Pumphouse.JPG|Pumphouse
File:RCAF St. Thomas Hangar Airside.JPG|Hangar, apron side
File:RCAF St. Thomas Hangar Furnace Side.JPG|Hangar, furnace end
File:RCAF St. Thomas Hangar Door Side.JPG|Hangar, doors
</gallery>