Airport control tower (TWR)
WHAT AIRCRAFT IS TWR?
TWR is the ICAO aircraft type designator for the Airport control tower — not a plane — the control tower itself, wearing a transponder and broadcasting right along with the aircraft. It has watched every single one of them leave without it. When you tap a blip on a radar scope, flight tracker, or spotting app and see "TWR", this is what's overhead.
Want to catch one in the wild? Open the live scope, enter your postcode, and watch for the type code on any contact. Tap it for the airline, registration, route and a photo.