When did Indiana Jones learn to fly a plane?

Question

Consider the following sets of dialogue.

The first is from Indiana Jones and the Temple of Doom (1984) and the second from Indiana Jones and the Last Crusade (1989).

From Temple of Doom:

Willie: No one's flying the plane!

Indy: Oh, boy...

Willie: They've all gone! You know how to fly, don't you?

Indy: No. Do you?

Willie: Oh, no. Oh, my god!

Indy: How hard can it be?

From Last Crusade:

Indy: Come on, Dad. Come on!

Jones Sr.: I didn't know you could fly a plane.

Indy: Fly, yes. Land, no.

So on to my question. When did Indy learn to fly a plane? Are we meant to understand that he's learned to fly since the events of Temple? Or are we meant to understand that due to the events of Temple, he now has a basic working knowledge of how to fly a plane?

Answer 1

According to the Lost Journal of Indiana Jones, he learned how to fly a Ford Tri-Motor Airplane following the events of The Temple of Doom.

Determining that killing Jones was worth the cost of the plane, Lao Che signaled the pilot and co-pilot to ditch the plane. After refueling in Chungking, the plane traveled west instead of south towards the scheduled destination. While the passengers slept, the pilots dumped the fuel, took the only parachutes aboard and jumped to safety over the eastern Siwalik range2. Jones and his companions awoke, realized that a crash was unavoidable, and jumped out of the plane with an inflatable raft. The plane crashed into a mountaintop near the Pindari Glacier.

After the encounter, Jones found an instruction manual for a Ford Trimotor and kept it in his journal, along with a note to learn how to fly a plane. By 1938, he had learned how to fly a plane, but not land.

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Note: The Temple of Doom is considered a prequel as it is set in 1935 and Raiders of the Lost Ark is set in 1936. So, Indiana Jones learned to fly (but not land) in the time frame between The Temple of Doom and The Last Crusade.