Around the 2:15 mark, the cast of characters are getting ready to make their escape in the plane. They use on of those manually portable airplane staircase/gantries common throughout most of commercial aviation history.

This item shows up routinely during the film, and you can see that it's on that must be manually installed.

The cast enters via the gantry, and then closes the door. The plane then accelerates to take off. Magically, this disappears (they go straight, and even if they were to turn right off the bat -- assuming you know how airplanes can turn on the ground -- the gantry would have struck the plane).