That is an increase of 7.7% compared with the same period in 2023.
The West Sussex airport recorded half-year revenues of £488 million, a rise of 15.3% from a year earlier.
Underlying earnings were up 13.9% year on year to £268 million, with net profit for the period up 33.8% at £106 million.
Gatwick chief executive Stewart Wingate said: “With the growing demand for travel, we are experiencing one of our busiest summers yet.
“Thanks to robust planning and close collaboration with our partners we’ve had a strong start to 2024, ensuring a reliable and enjoyable experience for our passengers.
“I am delighted that we have once again achieved good service levels, as evidenced by meeting 100% of our service measures.
“Our teams have worked incredibly hard to achieve these results.
“As we continue to grow our network and offer more choice for passengers, we are working towards our vision to be the airport for everyone, whatever your journey.”
Service measures include factors such as the availability of seating in departure lounges, waiting times at security, and baggage delivery times.
Gatwick said its focus on developing new long-haul routes to airports in the Middle East, Asia and North America is attracting “a wider range of passengers”.
Recent new services include the June introduction of Singapore Airlines flights to and from Singapore Changi Airport in June, while Air India launched flights between Gatwick and Bengaluru (Bangalore) this week.
The latest phase of Gatwick’s planning application to bring its existing emergency northern runway into routine use ends next week.
If its request is approved, the runway could be used regularly by the end of the decade.
Mr Wingate said: “Through our northern runway project, we are demonstrating our commitment to growing sustainably, in line with our decade of change sustainability strategy and government policy.”