What aircraft is N23721?

N23721 is a Boeing 737-700 (B737).

United Airlines, going by the callsign it flew under when it was caught.

What is the ICAO 24-bit address of N23721?

A22539. The Mode S address is assigned to the airframe by its country of registration and stays the same from flight to flight.

On 2026-11-09. Our receivers have heard it on 48 days since 2026-09-12.

N23721 is a Boeing 737-700 operated by United Airlines. It was built by Boeing. 2 pilots have caught this exact tail in Skydex.

N23721 picked up by 6 Skydex receivers (North Carolina, Kentucky, Georgia), 48 sightings since 12 Sep 2026, last on 9 Nov 2026.

Asheville NC — 🇺🇸 United States of America · North Carolina · run by @parker-redding — 1 airframe, 19 sightings, last 2026-11-08
sdf-feed68 — 🇺🇸 United States of America · Kentucky · run by @sdf-feed68 — 1 airframe, 18 sightings, last 2026-11-04
BakerC - FiberflyTower — 🇺🇸 United States of America · Georgia · run by @ebc1613 — 1 airframe, 14 sightings, last 2026-11-09
Docking-Bay-94 — 🇺🇸 United States of America · Pennsylvania · run by @pfshady — 1 airframe, 11 sightings, last 2026-11-06
Dexter — 🇺🇸 United States of America · Ohio · run by @nightlonk — 1 airframe, 10 sightings, last 2026-11-09
home — 🇺🇸 United States of America · near Philadelphia · run by @callmerafiki — 1 airframe, 10 sightings, last 2026-11-09