To clarify: The only "perfectly good airplane" has a jump door.
Not jumping would be like having a hot beautiful young lady, you go to her place and she invites you in. And you say, naw, think I will just stay in the truck???????
Taken hundreds on tandem jumps, Accelerated Freefall and static line. Instructor rating on all from USPA. D# 9363 Also a private pilot and have flown many more in Cessna 182 and 206. Both without doors and with a jump door installed. Rather jump than fly any day.
And for the guy that said you had to have oxygen to jump from 14,500. You can easily fly a turbo aircraft at 12,500 and "jump up" to 14,500 in a few seconds and be legal. Done every day at drop zones around the country.