Holiday Extras took £1,275,000 in gross revenue on August 5 – beating its previous record sales day on July 1.
It is only the second time that the Kent-based company has recorded more than £1.25 million in gross revenue on a single day.
Matthew Pack, group chief executive, said: “While there’s a lot of pessimism at the moment about the exchange rate and consumer confidence, what we’re seeing instead is millions of British holidaymakers determined to book their week or two in the sun.
“With a few sensible precautions, people will still be able to travel whatever the Brexit outcome.
“The next Brexit date isn’t until the end of October and, according to the regular poll we’ve been running since last year, only 2% of British travellers are still putting off their summer holiday plans because of Brexit jitters.
“So we’re delighted, but not surprised, to have seen our second all-time record booking day already this summer.”
Holiday Extras makes bookings for about eight million travellers each year, selling add-ons such as UK airport parking, airport hotels, airport lounges, car hire, airport transfers and holiday insurance.