ICTS clients include Air Canada, Air France, All Nippon Airways, American Airlines, British Airways, China Airlines, Delta Air Lines, EasyJet, Emirates, Japan Airlines, KLM, Lufthansa, Qantas, Singapore Airlines, South African Airways, United Airlines and US Airways.

See: http://www.ictseurope.com/clients

If you look at local sites such as http://www.icts.co.uk you will see they have further clients such as Aer Lingus and Virgin Atlantic too.

To avoid ICTS, you are best avoiding airports where they operate! But they operate at a lot of them - not just the ones at the main site. In UK and Ireland, the local site shows they are at Manchester, Newcastle, Belfast, Birmingham and Shannon (as well as LHR and LGW as listed on main site).