It is reported The RAF and GCHQ helped prevent a terror attack in Bath, as well as three other places in the UK.
The Daily Express claim the RAF overhead commercial pilots discussing potential targets on their radios.
The jihadist attacks were being planned for London, Bath, Brighton and Ipswich in the week after the Paris massacre.
Despite speaking in Arabic and using codes, British spies were able to decode what the men were saying.
It is believed one of the two pilots, who were both intercepted, was on an intelligence service watch-list.
Both men were believed to be sympathetic to Islamic State.