Jetb, I think you actually have to have a squad to upload the nose art. If it isn't uploading in the DA, have you formed your squad there yet?
From the tower click on club (on the clip board) and see if your squad is active in the DA. If its not, just form it there and then click on upload noseart.
If you still can't upload it check to make sure that it is in the squads folder (program files--->HTC--->>Aces High---> squads), and that it is 64 x 64 and 256 colours. It will be listed as Jetb123.bmp
If it ain't there, put it there.
If it is there, it may just be awaiting approval. Patience is the answer there.
cheers,
RTR