Looking for an airplane read? Try At Risk by Stella Rimington. The author, Dame Stella Rimington, was the Director-General of the British Security Service MI5 from 1992 to 1996. Appropriately, her 2004 book is a spy novel.
In At Risk, protagonist Liz Carlyle is an agent-runner in MI-5's Joint Counter-Terrorist Group. An Islamic terrorist group has deployed an "invisible", defined as "an ethnic native of the target country". This "invisible" is suspected to be assisting another militant operative that British security agencies believe was smuggled into the country. Liz leads the frantic effort to find these two security threats and figure out who is their target. At Risk is at its best when Rimington writes about her character's work within the security service, interactions between MI-5 and other agencies, and the pressure-filled investigation of the security threats. Less interesting are the little dramas in Liz Carlyle's personal life. However, as a spy novel, At Risk is a nice read.
If you read At Risk and enjoy it, know that there are three more books by Rimington featuring Liz Carlyle: Secret Asset, Illegal Action, and Dead Line. Dead Line is available on amazon.uk, but as of today it is not on Amazon in the U.S.