More than three-million passengers are expected to travel through Heathrow over the Easter holidays.
The busiest day will be this Friday when 220,000 people will pass through Britain's biggest airport.
Airport bosses say that they are laying on additional staff and there will be pre-flight play areas for children.
Those travelling by rail may have to contend with engineering work, with nearly every train company having to bring in rail-replacement buses on some routes.
A number of South West Trains services out of Waterloo will be affected, as will Greater Anglia services in and out of Liverpool Street.
Passengers travelling with First Great Western will have to take buses on some routes in Berkshire, Wiltshire and Hampshire, with Reading one of the stations affected.
Buses will also replace trains on some London Midland routes out of Euston station, while Southeastern will be running buses instead of trains due to seven lots of engineering work over the bank holiday weekend.
Passengers heading for Gatwick Airport in West Sussex will have to contend with a half-hourly service, as fewer lines and platforms are available through East Croydon in south London.
But the Association of Train Operating Companies and Network Rail have said the vast majority of passengers will be unaffected by the Easter work. The two companies added that the number of replacement buses had dropped 34% compared with Easter 2011.