Toward the end of the movie when "Tommy" runs out of the dance to the plane and is having flashbacks, Claire runs up to the cockpit area of the plane. The scene flashes to "Tommy" in the cockpit, then back to Claire, who is now running in the same manner toward the door at the back of the plane.
After Claire leaves in the car to look for Joe, the car has an older period-correct rear tag with no validation decals. In the following scene, it has a more modern California blue and gold rear tag with validation decals. In a subsequent scene after she leaves the VA hospital, there is no rear tag on the car. When she arrives at the airfield and first meets Will, the original period-correct tag is back on the car.
The size and style of the wedding ring changes from when Claire gives it to Ruby and when Joe gives it back to Claire.
When the B-24 is being test flown, it is shown retracting its landing gear on take-off. A moment later the aircraft is shown with the gear down, then up again.
The plane at the airfield where Tommy is working circa 1946 is marked "United States Air Force". This term was not used until September 1947. Until that time the branch was called the United States Army Air Forces. Additionally, army air force planes at the time were never labeled as such, instead using insignias for identification such as the ones shown on the B-24.
When the B-24 is being tested prior to flight, Will and Tommy are doing the pre-flight checklist with headphones on and no microphones shown. They are talking in normal voices, which would not be able to be heard above the engine noise. This same error is repeated during flight.
When the B-24 lands at the little airstrip at the end of the film, a modern airport navigation aid can be seen in the background.