Spanish police say they suspect a British man and his son of pointing green laser beams at incoming airliners on the Costa del Sol - an offence that can incur an enormous fine.
An off-duty police officer reported seeing them aiming laser pens at jets from a hotel balcony in Torremolinos, near Malaga, on Tuesday night.
The British man is 41 and his son 15, police said (in Spanish), giving no further details about them.
Three pilots reported being dazzled.
They told the Malaga airport control tower, on Spain's south coast, that green laser beams had troubled them as they prepared for landing.
If found guilty, the two British holidaymakers could face a fine ranging from €30,001 (£27,280; $35,425) to €600,000 for endangering flight safety.
Spanish authorities have not yet confirmed any charges.
Raúl Delgado, spokesman for Malaga's air traffic controllers, said the laser beam "enters the cabin and starts bouncing off the windows, hampering the pilots' view of the instruments, causing much interference just when great concentration is needed for landing".
In the UK, the number of such incidents was 1,258 last year - more than three a day on average.
The UK government is tightening the law to tackle the many dangerous incidents, envisaging prison terms for offenders.