Did you know that they just determined that there is a different strain of Covid 19...
Did you know that they just determined that there is a different strain of Covid 19 which mainly spreads via people at the airport, and which is always deadly?
It’s a terminal illness.
This is dark humor, an airplane joke, a covid joke, and also an awful pun. Joking about death is dark humor, but really this isn't that dark compared to some dark jokes. The pun is that the word terminal can refer to a place in an airport, but it can also refer to a disease that will kill you.
So, the joke is funny because you think when you hear the setup that the year just got worse because covid is now much more deadly, but instead you find out that it was all a lame pun.