A trainee pilot suffered laser burns to one of his eyeballs when a beam was shone at his cockpit during a flight, police said.
The incident was one of two involving laser attacks on aircraft taking part in training flights from Oxford City Airport in as many days.
Detectives have managed to trace the rogue beams, which were deliberately aimed at the cabin, to Chipping Norton and Carlbury in Oxfordshire.
Thames Valley Police are appealing for any further information.
A spokesman said the 21-year-old pilot ‘was injured with the light from the laser causing a suspected laser burn to his eye’ on February 4.
He added: ‘The aircraft landed safely and the pilot was taken to the John Radcliffe Hospital for treatment. The extent of his injury is unknown at this time.’
The second incident, at around 5.45pm the following day, involved the targeting of an aircraft approximately three miles north of Charlbury.
Nobody was injured and the aircraft landed safely.
Investigating officer PC Renee Gabbey-Cristofini said: ‘These were extremely reckless acts which placed both aircraft in significant danger.
‘The trainee pilot of the first aircraft suffered injuries to the back of his eye as a result of this attack and the injuries may result in him being unable to fulfil a career in aviation.
‘The recklessness of such acts not only endangers the aircraft and all passengers on board but also those on the ground, as attacks such as this seriously jeopardise safety.
‘We do not know exactly the origin of these laser attacks, but given that they both happened in close proximity to each other, I am appealing to anybody who has any information that can assist this investigation to contact police.
‘Shining laser beams into the sky at aircraft is not acceptable and we are investigating thoroughly. I am urging anybody who may have any information to please get in touch.’
Anyone with information can also make a report online or anonymously call independent charity Crimestoppers on 0800 555 111.