The posts from EastMids and gilesdavies are both spot on. In addition EMT do not have the right type of carriages for short case laden journeys. Each carriage has only 2 single doors at each end, very restricted loading/unloading. That set up would be tolerated for trains from the north.EMT would not want airport passengers London to Luton. The stopping time at Parkway would make the timetable unworkable. I remember back in the 1970s fast trains to the north were not advertised at St. Pancras as stopping at Luton even though they did,to pick up only. Can people be kept of EMT trains ? Yes the tickets issued at Luton are for Thameslink trains only. As already stated fast Thameslink trains are 30 mins.