What joke is it that three people fart?

There are two maintenance workers who love to drink at Beijing military airport. One day, when they were on the night shift, they were addicted to alcohol, but they didn't bring any wine and there was no shop nearby.

"I heard that jet fuel is the same as liquor. Have some. " One person suggested.

So, the two men took out the fuel in the tank and drank as drunk as a fiddler.

The next day, one of them woke up and was surprised to find that, unlike usual drinking, he had neither headache nor nausea. At this moment, the telephone rang and he picked it up.

"ah! Are you all right? " It's the voice of another mechanic.

"Nothing, don't say, jet fuel is really good, and I don't have a headache or nausea."

"Me too, but ..." "But what?"

"Did you fart after getting up?"

"No."

"Then be careful, I am in Hainan Island now."