You can find plenty of cheap international flights from Houston to London operated by world-class carriers. The city of Houston in Texas is served by George Bush Intercontinental Airport (IAH) while London in England has five international airports: London Heathrow (LHR), London Gatwick (LGW), London Luton (LTN), London City (LCY), and London Stansted Airport (STN). When you are flying out from Houston to London Heathrow, you will be boarding your flight at George Bush International Airport (IAH) and will be landing at London Heathrow Airport (LHR) which is the main gateway to London for international travelers.