The campaign is being used to promote Club Carlson, a rewards scheme available at more than 1000 hotels worldwide, and was booked with JCDecaux Airport through airport specialist PSI with US media agency Riley Hayes.
The ads, made by Edinburgh-based agency Teviot Creative, use the tagline 'Welcome to a whole new world of hotel rewards' and direct passers-by to clubcarlson.com.
Booked with JCDecaux Airport through PSI, the campaign will run for four weeks throughout May and promotes Club Carlson, a rewards scheme available at over 1,000 hotels worldwide.
Steve Cox, marketing director of JCDecaux Airport, said: "HEX Motion Plus gives one advertiser ownership of the key points of transition between the Heathrow Express and the Heathrow terminals, surrounding the passenger with the advertiser's brand message."
To accompany the HEX Motion Plus activity, Carlson Hotels has also booked sites in departures and arrivals at Heathrow Terminal 4 and Terminal 5, including the 'Zonal Beacons', which mark the zones in the check-in area at Terminal 5.
A spokeswoman for JCDecaux Airport said the Heathrow Express reached 5.3 million passengers a year and has a 96% ABC1 profile.