DeltaRules From United States of America, joined Sep 2001, 4190 posts, RR: 8
Reply 2, posted (13 years 8 months 2 weeks 2 hours ago) and read 1739 times:
I'm not entirely sure about this, but this is what I think I heard-.
I think that the 600s were missiles, 200s twin-engined propeller planes (Boeing 247) & 400s were gonna be helicopters. 700s became jets because the number was next in line.
Not entirely sure, but it's something like that.