Not the normal flight path of an airplane, anyway.

I don't know which kind they hit. But based on what's on the left side of runway 31L, I suspect it was a runway remaining distance sign, those are all black, and around 5' tall, and vaguely resembles the passenger photo of something black embedded in the wing.

Edit: Comment #77 in this forum thread is interesting if a true account. https://www.airliners.net/forum/viewtopic.php?f=3&t=1420137&...

It's a runway marker sign. They are pretty low, and in the grass, and have breakaway mounts. This sort of thing: https://blog.klm.com/assets/uploads/2015/08/Signs_7.jpg

The aircraft would have been way off center of the runway, with the left wing literally dragging the ground.

JFK runway 31L is 200 feet wide, an A321 has a wingspan of 112 feet. The wings are 12 feet from the ground at the fuselage, and maybe two feet higher than that at the wingtips. The photos[1] show heavy abrasion under the left wingtip, presumably it was dragging the ground.

[1] https://imgur.com/a/rKu8cUC

Fron TFA, it was taxiing when it hit the sign.

Edit: Disregard this, AV Herald links provide more info.