A massive switch of terminals by airlines using Los Angeles international airport (LAX) starts tonight and is due to be completed by Wednesday morning.

Described as one of the largest terminal moves in the history of commercial aviation, Delta Air Lines will relocate from Terminals 5 and 6 to Terminals 2 and 3.

Passengers using the California hub have been urged to plan ahead given that 21 airlines will move to different terminals over the move period.

Los Angeles World Airports chief executive, Deborah Flint, said: “It all comes down to our guests being informed and taking the necessary actions to make sure they are in the right place at the right time to catch their flights.

“During the relocation and in the weeks following, passengers are advised to check in online, print or download boarding passes, and check terminal and gate information before coming to LAX.

“They should also arrive to the airport earlier than normal. Once at LAX, passengers should check flight and gate status on flight information display boards in each terminal to ensure they are in the correct location.”

Delta’s relocation to Terminals 2 and 3 required an extensive construction effort, which included building new baggage systems and offices, employee lounge areas, ramp offices and IT systems for all of the airlines moving into Terminals 5 and 6 and for Delta’s new space in Terminals 2 and 3.

The switch is a precursor to the Delta Sky Way at LAX, Delta’s $1.9 billion plan to modernise, upgrade and connect Terminals 2, 3 and the Tom Bradley International Terminal over the next seven years.

Ranjan Goswami, the airline’s sales vice president for the west said: “Delta has planned for this move for nearly a year, and I’m confident that our team will make this as smooth as possible for our customers.

“But we also need our customers to be prepared if they are travelling during the relocation.”

Los Angeles Board of Airport Commissioners president, Sean Burton, added: “The ‘LAX on the MOVE’ team is continuing to plan, counting down to May 12.

“When the board approved a new lease and license agreement for Delta Air Lines last summer, chief among our priorities was improving the guest experience at LAX.

“Delta’s plans for Terminals 2 and 3 fit this vision, and bring us one step closer to the LAX of tomorrow.”