My 24 years old son has just returned from Florida for the Christmas season.

He is current ly on a US visa and attending flight school in Naples.

He flew from Fort Meyers to Orlando and then a connection to New York where he boarded Aer Lingus flight 104 to Dublin and the Aer Lingus 202 to Manchester.

He somewhat surprised me by telling me that his passport was checked once at New York and that's it.

At Dublin he was directed straight through to his connecting flight and at Manchester he was treated as a domestic flight passenger so no checks.

Is this normal?

Strikes me as seriuous breach of security.