Planes used by the Royal family could lose their red, white and blue livery markings for security reasons because they look too distinctive.
The Royal aircraft could lose the union jack
The Ministry of Defence said attempts are being made to make the jets, formerly known as the Queen's Flight, more civilian looking.
The changes are being considered amid current global fears over terrorism.
Removing the striking Union Jack flags from the tail fins of the aircraft is one of the possible changes.
The Royal Squadron, also known as No 32 squadron, is made up of two four-engined BAe 146s and five twin-engined Hawker S125s.
As well as being used by the Queen, the Prince of Wales and other royals when on official duties, the planes also transport Prime Minister Tony Blair and other senior figures.
An MoD spokeswoman said: "We have to routinely overhaul the maintenance.
"We are looking at the possibility of changing the paint scheme slightly to make it look more civilian for security.
"The flag is one of the areas we could look at."
There have been no specific terrorist threats against the planes, the spokeswoman added.
"In today's climate, you want the aircraft to look as unobtrusive as possible," she said.
No decisions are likely to be made until next year.
King Edward VIII created the first King's Flight in 1936.
Since then an RAF unit has held the responsibility of providing air transport for the royal family for official duties.
In 1995, the Queen's Flight combined with No 32 Squadron, prompting a change in name and also moved from RAF Benson to RAF Northolt.
The BAe 146s can carry up to 23 people and the Hawker S125s up to seven.
Cost of official royal travel is met by the Royal Travel Grant-in-aid from Parliament, through the Department for Transport.
In 2002, flights with the Royal Squadron cost £476,000, according to a Grant-in-aid annual report.