We don't have identity cards, so would we have to show our passports anyway?
I tend to use my driving licence as ID when I fly within the British Isles.
I've never really understood the (so-called) libertarian argument against ID cards.
Personally,(as a freelance), I find my ID card very useful when asking for receipts/proving my identity etc.
I've managed to survive quite happily without having to pay for one.
I don't understand the point in having a passport and an ID card. It seems unnecessarily bureaucratic.