28 is not a record, from the info I heard years ago.......
...When UPS started their own flight department in late '87 and '88, one of the new UPS 747 captains (acquired) was 27 years old. The very firm, militaristic flight management at UPS harassed him and might have even fired him for a short period. Don't know the specific issues involved, but that was the jist of the story......
so, if he went to UPS as a captain at age 27, he might have even been younger when he initially checked out/typed on the 747? not sure which contract carrier he was originally from.......