Jobs at the National Air Traffic Service (NATS) in Swanwick could be under threat after the company lost out on a major contract.
The firm was outbid by German firm Deutsche Flugsicherung (DFS) to provide air traffic control services at Gatwick.
The service, which navigates planes travelling under 4,000ft, has been provided by NATS for 30 years, but after a competitive tendering process Gatwick announced the ten-year contract would go to DFS.
NATS will continue to navigate air traffic above 4,000ft.
Mike Stoller, director of operations, airports for NATS, said: “We are extremely disappointed that the highly competitive bid we submitted to Gatwick has been unsuccessful.
“We have added considerable value to Gatwick in recent years, building it to the point where with 55 movements an hour it significantly out-performs every other single runway airport in the world.”
The firm said it was too early to say if jobs would go.
Gatwick bosses said following a period of transition, it was anticipated DFS would start work in October 2015.
Chief executive officer Stewart Wingate said: “Gatwick operates the busiest and most efficient single-runway airport in the world. Naturally safety comes first in everything that we do.
“DFS is a well-known and well-respected provider in this industry and across Europe and has demonstrated a forward-looking approach to its business which matches our own ambitious plans to grow.”