Two teenagers without boarding passes got into an airport's departure lounge on the fifth anniversary of the 11 September attacks.
The airport said the pair would not have been able to board a plane
The 14-year-old girl and 15-year-old boy were arrested on Monday for alleged theft from a shop at Newcastle Airport.
The pair were not booked on to any flights and had no boarding cards.
They were screened in the security search area and the airport said more checks would have meant they would not have been able to board a plane.
In a statement, the airport said: "Both individuals passed through the security search area and were therefore subject to rigorous body and hand baggage searches in accordance with Department for Transport regulations.
"Consequently, they posed no risk to airport or airline security. However, we can confirm that they did not have valid boarding cards.
"The Department for Transport have been informed of the incident. They are satisfied that the correct screening procedures were performed on these individuals and, as such, have confirmed that they are not concerned about the incident and will not be carrying out any further investigation.
"There was no risk that these individuals would have been able to board an aircraft. Department for Transport regulations require that all boarding cards are checked at the departure gate, and a subsequent check is conducted on boarding the aircraft, before access to the aircraft is permitted.
"In light of this incident, the airport company has reviewed its access control procedures within the security search area and has taken steps to ensure there can be no such repeat in the future."
Northumbria Police said the pair had been bailed pending further inquiries.
Last month, a 12-year-old boy, believed to be from Cumbria, managed to board a plane from Gatwick Airport without tickets during a security alert.