"Just as your (Polish) leadership proved itself in the tank coalition, I believe that it will manifest itself in the planes coalition," Zelenskiy said in a speech on a square in Warsaw.
The Ukrainian leader said Russia would not defeat Europe while Ukraine and Poland were working closely together.
"Here, shoulder to shoulder, united on this square by the spirit of freedom, of a great history and of a glorious victory, which we bring closer together,” he said.
Speaking before Zelenskiy, his Polish counterpart Andrzej Duda said Russia had committed war crimes in Ukraine which must be punished.
Ukraine, which hopes to launch a counteroffensive in the coming weeks or months, wants to secure advanced fighter jets such as the US F-16 from the West to help fight back Russian invaders and defend itself from air strikes.
Warsaw is a close ally of Kyiv and helped galvanize support in the West to supply main battle tanks to Ukraine as part of a coalition of powers, a move that initially hit a diplomatic impasse that was then overcome.
Reuters