Passengers were advised to check in as normal at Stansted Airport today despite the first of a wave of strikes by ground staff in a row over rosters.
Contractors Swissport said the Essex airport will be open as normal, with no disruption to services.
Members of the GMB will walk out for 24 hours from 5.30am today, followed by strikes from 5.30am on Saturday until 5.30am on Monday and from 5.30am on Saturday June 2 until 5.30am on Wednesday June 6.
The June 2-6 strike includes the two jubilee bank holiday days of Monday June 4 and Tuesday June 5.
GMB suspended threatened strike action earlier this year over the introduction of new rosters which the union said would have led to a reduction in incomes of members after the company agreed to enter talks.
The discussions broke down last Friday.
GMB organiser Gary Pearce said: "GMB negotiators have been in talks to reach an agreement to resolve this issue since the agreed suspension of the strike action scheduled over Easter.
"It is a shame that Swissport has made and then withdrawn a number of proposals including a return to the original four-days-on and two-days-off roster which would have settled the dispute. The proposals were withdrawn last Friday."
A company spokesman said: "Swissport can confirm that, with contingency plans in place, the airport will be open as normal and expects no disruption to their services. Passengers are therefore advised to check in as normal with hold baggage, which can be checked in for all flights.
"The action is being taken by the trade unions following the rejection of a revised roster proposal which has been put to members by a joint working party comprising both union and management representatives. The revised roster would avoid the necessity of imposing compulsory redundancies.
"The industrial action affects only staff engaged in baggage handling and despatch at Stansted Airport. It does not affect check-in or other customer-facing staff or any staff at other bases at which Swissport operates. Swissport handles flights for Ryanair, Thomas Cook, Thomson, AtlasJet and BelleAir."
Ryanair said it will operate a full schedule of flights to and from Stansted during the strikes.
Spokesman Stephen McNamara said: "It is irresponsible of the union to hold passengers to ransom each year. Ryanair will not allow these unions to blackmail or disrupt our passengers.
"If this threatened industrial action goes ahead we will ask passengers to check in online and travel with carry-on luggage only."