Maybe the lack of distortion through aircraft windows can be established by photographing the stars just above the horizon and verifying that they are not distorted into a curve like flat earthers suppose the horizon to be. A low distortion wide angle lens could be used and the alignment could be checked using a picture of the same stars from a mountain top. The two pictures could be overlapped to verify star positions. It would be desirable for the stars in question to be positioned along the middle height of the picture frame where lens distortion is smallest. Can we photograph stars from an airliner or would the cabin lighting blow out the exposure? It may be necessary to bring a black cloth to cover the inside of the window around the camera and photographer. Stars may require long exposures which could be spoiled by even slight airplane movement.