The aircraft, carrying 62 people, was travelling at about 900 feet (274 metres) as it prepared to land at Newquay Airport in Cornwall on Wednesday afternoon when it reported a near miss with the drone which was flying alongside.
"This is an incredibly concerning incident; the close proximity of the drone to the passenger aircraft shows a complete disregard by the operator for public safety," said Inspector Dave Meredith from Devon and Cornwall Police.
Officers searched the nearby area but found neither the drone nor its operator.
The incident was the latest in a series involving drones and commercial aircraft.
In April, police said a British Airways passenger jet was hit by what most likely was a drone as it prepared to land at London's Heathrow Airport, Europe's busiest airport.
The plane landed safely but the increasing use of drones for commercial purposes, photography or leisure has led to fears they pose a serious risk to passenger aircraft.
Britain's Civil Aviation Authority last year issued a warning after seven incidents in less than 12 months where drones had flown near planes at different British airports.