Gatwick and Heathrow are to install anti-drone technology following the disruption at the Sussex airport before Christmas.
Gatwick has spent £5 million to prevent future attacks, and Heathrow confirmed it would be buying systems.
The equipment, which can detect and jam communications between a drone and its operator, was deployed by the RAF on a roof at Gatwick last month.
About 1,000 flights were cancelled over three days due to drone sightings at Gatwick.
More than 140,000 passengers were affected during 36 hours of chaos between December 19-21.
The two London airports have not disclosed the equipment they plan to use in future.
A Gatwick spokeswoman confirmed the airport had invested in new anti-drone defences after the disruption.
A Heathrow spokesman told the BBC: “The safety of our passengers and colleagues remains our top priority.
“Working closely with relevant authorities including the Met Police, we are constantly looking at the best technologies that help remove the threat of drones.”
Sussex Police, which is still investigating the disruption, says it was caused by “numerous instances of illegal drone activity”.
The force said it has “relevant sightings” from 115 witnesses – 93 of whom it described as “credible” – including airport staff, police officers and a pilot.