Actual teletype machines? No. (Though flight strip printers used at ATC consoles are basically mini teletype printers.)

However, AFTN (used for disseminating flight plans and weather between ATC facilities) still uses landline modems running TTY-originated protocols.

In the US we've moved moved off AFTN in favor of AMHS/X.400, as have most countries - but my understanding is there's still some last holdouts that haven't fully switched over.