Officials have denied any breach of safety after two planes were pictured apparently flying perilously close together over east London.
The aircraft - a DHL plane and a Japan Airlines jet - were reportedly seen flying over West Ham FC's Upton Park ground just after 1500 GMT on Saturday.
The Civil Aviation Authority said no near miss had been reported and it was impossible to tell how close they were.
DHL said the picture was deceptive and the planes were not close together.
It said both planes had landed at Heathrow with no safety lapses.
The photographer who captured the image told the Sunday Mirror he started taking photos after seeing the planes apparently coming together "on a collision course".
But a spokesman for DHL said photographs could be "incredibly deceptive".
"In the picture, they look like they are close together but it doesn't mean they are. And in fact they were not," he said.
"If there had been any incident of them being close together, there are all sorts of systems which would have gone off, both in the plane itself and at air traffic control - but there wasn't any report of an incident."
The spokesman said there was no question that either aircraft had strayed from its proper path, which should mean there was a distance of some two and a half miles between them.
British Air Line Pilots Association chairman Captain Mervyn Granshaw described it as a "fluke photograph".
He explained how visual factors conspire to make the planes could look closer together, but safety measures meant they could not be in such proximity.
While the lower plane was a A300, a smaller freight plane, the one behind was a Boeing 777 - a larger, passenger plane.
The difference in size, angle of the photograph and the distance it was taken from - the ground to two planes at high altitude - would exaggerate the effect, he said.
Radar and modern electric or pressure altimeters to measure planes' position; warning systems for pilots and air traffic controllers; and other modern safety measures, meant planes were kept at a separation of 1,000ft, he said.
If they come closer, warning systems alert pilot and controllers, and reports are filled out.