Actual parachutist here… not as qualified as RiggerRob or JerryBaumchen, but back in the day I did own and refer to a Poynter book.
C9’s (28’ flat circular canopies) and 24’ flat circular canopies were more common for Air Force and Army paratroopers. A 24’ flat circular puts you down in a pretty noticeable hurry, but in those days it was rare for the main not to open at all; instead they’d open and throw the reserve out into a malfunction to get more fabric over their heads. The Navy conical (a gold standard of early reserves because it landed slower than the 24’ and packed smaller than the 28’) was generally packed into an NB-6 container I believe. That’s a back container, but remember that WW2 didn’t have a lot of Navy guys who planned on jumping…
At the time of the hijacking, a 28’ flat circular with a 24’ flat circular reserve would have been common, and readily available from any local DZ or rigger. A 26’ conical reserve or a 28’ flat circular reserve would have been slightly harder to get, but not uncommon (but maybe not the first things volunteered, as they were less common). A 24’ canopy in a main (back) container would have been unlikely.
Mainly because most jumpers jumped for fun, and few people who were heavier than Twiggy would deliberately choose a 24’ canopy. The 28’ reserves were desirable because the big boys needed them, and the 26’ conicals because of what I already said. So a 28’ main and a 24’ reserve would be what I’d have offered 7 years later, when I was an active rigger.
Enough pedantry. Back to the topic
Wendy P.