From Chelmsford train to Liverpool Street Underground Station, Tube to King's Cross St. Pancras Underground Station, walk to London St Pancras International, then train to Luton Airport Parkway. 1 h 30 min £28. From Chelmsford City Centre, Bus Station (Chelm Bus Stn) bus to Stansted Airport, Coach Station then bus to Airport Bus Station. 2 h 14 min £16. From Chelmsford drive to London Luton Airport (LTN). 1 h £11. From Chelmsford towncar to London Luton Airport. 1 h £153.