How can Finn pilot this vessel?

Question

In The Force Awakens, it's mentioned at least twice that Finn is not a pilot.

First, when Finn rescues Poe:

Poe: Why are you helping me?

Finn: Because it's the right thing to do.

Poe: You need a pilot.

Finn: [chagrined] I need a pilot.

And later, when Finn and Rey are trying to escape the First Order on Jakku:

Finn: We can't outrun them!

Rey: We might... in that quadjumper!

Finn: We need a pilot!

Rey: We've got one!

Finn: You?

However, at the end of The Last Jedi, we see Finn joining the final battle on Crait in one of the ski speeders. Where did he learn to fly so quickly?

During my initial viewing of the film, I presumed that he only joined the battle out of desperation, as by that point the Resistance had lost most of its remaining members (with only a few dozen successfully making it to Crait). However, from my observation, he seemed to pilot it fairly well for someone who's supposedly new to flying. Are speeders of that type just easier to pilot than other types of hovering/flying vehicles?

Answer 1

In a deleted scene from The Force Awakens, we can see that Finn is a pretty decent speeder pilot. What he seems to lack is combat flight skills, hence why he busts Poe out for his daring escape.

A hasty search took them to a parking area filled with a smattering of vehicles. From the varied assortment, they settled on an isolated snow speeder. Between Finn’s training and Rey’s knowledge of machines, they managed to get it fired up.

_{^{The Force Awakens - Official Novelisation}}

Even by The Last Jedi (when he's had some pilot training courtesy of Rose on board the escape shuttle) he's still pretty poor at it, as this exchange with Rose shows.

“What? I’m the guy who’s most familiar with what they’re going to throw at us. And the only one who’s ever seen that big cannon of theirs.”
“This isn’t like flying a shuttle, which you were kind of bad at.”

_{^{The Last Jedi: Expanded Edition}}

Answer 2

Finn could drive speeders, but could not fly spacecraft.

The reference to driving is deliberate: in SW, various types of speeders perform the same functions as cars in our universe. Although speeders technically do fly, apparently they are much easier to use than space fighters like an X-wing or TIE fighter. In episode 2, we see thousands of them on Coruscant, while trained spacecraft pilots like Poe are essentially specialists.

Finn, as an average First Order stormtrooper, did not receive training to become a space pilot, but could operate speeders. This is similar to most soldiers in modern armies being able to operate cars, but not fighter jets.

Answer 3

My men are exceptionally trained. Programmed from birth.

We hear General Hux say this, and it is very probable that the First Order programs all of the soldiers to have the basic ability to fly, although if some showed some more talent than others, they could be placed as a pilot in the First Order. Finn could have shown no special talent to fly, having just the basic ability to fly, and be moved to a different department, sanitation.