Police who found the three boys who went missing four days ago said there may have been a plan to "spirit them out of the country."
They failed to return to their foster carers' home in Sunderland, after setting out on a tea-time bike ride to a local park.
Instead, they caught a Metro to Newcastle, then took a pre-booked taxi to London and spent two nights in the capital before heading for Birmingham.
Superintendent Alan Veitch, who led the major investigation to find them, said it was "entirely possible" that the plan was to get the boys out of the country.
More top news
A look ahead at a wintry weekend forecast.
More than £55k has been raised to help Alan Barnes, a disabled pensioner, relocate after an attempted mugging outside his house.
Over 30 airports were nominated in for Top UK airport, but a satisfaction rating of 86% saw Newcastle Airport claim the top spot.