It's talking about the Genocide in Gaza, which Biden has been supplying with arms. OP is conveniently ignorant of the fact Trump said Israel should "finish the problem", he has promised to ban immigration from Gaza, and that Trump's press secretary claims Trump has done more for Israel than any other president.

I don’t understand the meme.

Background:

• https://theintercept.com/2024/01/10/biden-israel-genocide-lawsuit/

• https://www.independent.co.uk/news/world/americas/us-politics/biden-genocide-lawsuit-court-hearing-b2485780.html

• https://www.aljazeera.com/news/2024/1/26/us-court-hears-civil-case-accusing-biden-of-complicity-in-gaza

Is America at war?

Yes.

Was Joe Biden personally flying bombers?

No.