Airport officials in northern England are investigating how an 11-year-old boy managed to get on a flight to Italy without a passport or ticket.

The boy took off from his mother and went to Manchester airport where he snuck through passport checks and the boarding gate without anyone noticing until he was en route to Rome.

His mother reported him missing on Tuesday at 12:40 p.m. while they were at a shopping centre in Wythenshawe, a few kilometres away from the airport.

Airline staff kept the boy on the plane when it landed in Rome. He was then safely returned to his mother in England at 9 p.m.

An undisclosed number of airport and airline workers have been suspended, although officials insist there was no security threat.

"The boy went through full security screening, so the safety of passengers and the aircraft was never compromised," the airport said in a statement.