An RAF aircraft has become the third plane to be targeted by a green laser in the space of three weeks.
Thames Valley Police said a beam was shone at a large four-engine C17 while it was flying over the Cassington and Eynsham areas of Oxfordshire.
The incident, which happened on Saturday at about 17:50 GMT, comes after two training planes were targeted on 4 and 5 February.
A student pilot suffered a "laser burn" to his eye in the first attack.
Leading Edge Aviation, a pilot training academy, said the 21-year-old man was taken to hospital, but was expected to make a full recovery and return to training.
None of the crew were injured in the second and third attacks and on all three occasions, the planes landed safely.
PC Renee Gabbey-Cristofini said police were linking the attacks due to the locations of them.
"These incidents are very concerning and pose a real threat to the aircraft, those on board and the wider public," she said.
"These are highly reckless acts and has the potential to cause a serious incident."
The constable said such offences have the potential to "carry a custodial sentence of up to five years".