It’s a happy day for London’s two largest airports, with both Heathrow and Gatwick reporting record-setting passenger traffic in 2014.

More than 73 million people passed through Heathrow’s terminals, or roughly twice as many as at Gatwick:

But Gatwick grew faster than its cross-city rival for the fourth year in a row. Its passenger traffic rose by nearly 8% last year, versus just over 1% at Heathrow:

In the same breath as they announced their new traffic records, however, both airports’ executives took the opportunity to launch the latest salvos in an increasingly acrimonious battle. For years the UK Airports Commission has been studying the options for boosting the capacity of London’s overstretched airports, and late last year it narrowed them down to a choice between new or expanded runways at either Heathrow or Gatwick, with a final decision expected later this year.

The lobbying to be the one that expands is fierce. Heathrow, which is already running near full capacity, recently attracted Vietnam Airlines away from Gatwick. Heathrow boss John Holland-Kaye said today that this “underlines that airlines can only make flights to many long-haul destinations viable from a hub airport like Heathrow.” In an interview last week, Holland-Kaye dismissed Gatwick as useful for jetting away for “holidays in the sun,” but not much else.

For his part, Gatwick finance chief Nick Dunn said that expanding Heathrow represents “a backwards step towards higher fares, less choice, and the monopolies of the past.” And of the “holidays in the sun” jibe, Gatwick CEO Stewart Wingate put out a tetchy statement accusing his Heathrow counterpart of patronizing his own passengers: “We would respectfully remind Mr Holland-Kaye that 70% per cent of travellers use Heathrow for leisure and one in five passengers fly from Gatwick for business.”

Heathrow and Gatwick are, in many ways, victims of their own success. The airports run closer to full capacity than most other big airports around the world, leaving little room for error when things inevitably go wrong. The latest airport punctuality statistics show that a quarter of flights at each one consistently run late:

The increasingly cranky war of words between airport bosses is somewhat entertaining—unless you’re a passenger stuck at Heathrow or Gatwick. Better for the government to make a decision about relieving London’s growing airport congestion as quickly as possible.