At $13,000 a ticket, it's not surprising that Indiana Jones had to spend so much time looting tombs.

But that's a circular argument! If the only reason for going on
an expedition is the killing and looting and the only reason
for the killing and looting is to pay for the next expedition,
they cancel each other out.

I blame Marcus. Taking advantage of his financial naivete. Oh yes, the museum will buy his pieces no questions asked, when Indy desparately needs a flying boat ticket to Marrakech.

What it would have taken to keep one of those things flying...

Landing and taking off on water is really hard on structure, so there's always something that needs to be tightened up, and those style of engines - aircooled and multi-cylinder monsters - live in a perpetual state of about to break.

Plus the navigation! This was before much in the way of electronic direction finders, so the plane would have a navigator who would use the old ship-board style of a navigator's protractor, stop watch and the like.

Tube-type electronics.... on and on.

It's amazing they got one in the air, leave alone to the next continent over.