London’s Heathrow airport, which has operated close to capacity since the start of the decade, boosted passenger numbers 1.4 percent to 73.4 million last year as airlines deployed larger jets to make the best use of slots.

Even so, the addition of 1.1 million travelers was less than half the 2.7 million extra customers who used London Gatwick, Heathrow’s chief rival for a new runway in southeast England, where the annual growth rate was 7.6 percent.

Heathrow needs a third runway to lift growth rates after as capacity to add flights becomes limited, with the number up just 0.2 percent to 470,695 in 2014. Gatwick, also shortlisted for expansion by a state Airports Commission, attracted 38.1 million passengers with its single runway last year.

“Airlines can only make flights to many long haul destinations viable from a hub airport,” Heathrow Chief Executive Officer John Holland-Kaye said in a statement, citing the recent move of Vietnam Airlines to Heathrow from Gatwick.

Gatwick said its record figures show that the U.K. needs an expanded airport the servies the widest range of travel modes, including low-cost flights with carriers such as EasyJet Plc, which Heathrow doesn’t generally provide.

“Airport expansion should be for the many not the few, and our broad range of growth underlines that Gatwick is the obvious solution,” Gatwick Chief Financial Officer Nick Dunn said in a statement. “Expand Heathrow and we take a backwards.”

The Airport Commission’s final recommendations are due later this year after the May general election.

This article was written by Kari Lundgren from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: A passenger aircraft is seen from the village of Longford as it descends to land at Heathrow Airport in west London. Toby Melville / Reuters