Captain Aigner was killed as co-pilot of a British Horsa Glider, #LJ 161, that was shot down during Mission ELMIRA (Chalk #9) on the afternoon of D-day, 06 June 1944. The Missing Air Crew Report (MACR) #6473 included the recollection of the Co-pilot and the Crew Chief of the C-47 that was flying in Position #10 on that Mission.

The Co-pilot, Duane Tressler, wrote: " I was the Co-Pilot on the airplane flying in Formation Position ten (10) on the right wing of the Tow-Ship which was towing Glider No LJ 161. The latter Glider cut-off normally and started a left turn. This was the last I saw of the Glider. (The cut-off was made over the LZW.)"

The Crew Chief, Arthur Perez, wrote: "I saw Glider cut-off normally, taking a 45 degree left turn and pushing nose down into a steep glide. Machine guns concentrated on the Glider (LJ 161) after puncturing our right wing. American Gliders were seen in fields below just as Glider LJ 161 cut-off."