I'd always recommend that you never take anything #Bitcoin-related through an airport.

Each metal backup plate is important for preserving a permanent physical record of (half of) your private key. ie. Half of your 24 seed words on one plate, and the other half on another plate, hidden in a different geographical location.

For 24 seed words, this provides 128-bit security for each half.

When traveling anywhere, you could email yourself 12 seed words (with an encrypted email account for belt and braces. eg. Protonmail), then do the same with the other seed words on a completely unrelated device, and unrelated email account.

If anyone views either half of your private key, they can't do anything without the other half.

NB. Splitting 12 seed words in two is a lot less secure (64-bit per half).