Bear in mind that AH3-era bombers (A-20, Boston, Ki-67, Ar 234, Ju-88) are based on 4096 x 2048 res bmp files. That means they have eight times the data and so will take around eight times as long to download as a 1024 x 1024 res skin.
Probably best then to go onto the AH Skins download site and download them from there.