The police have powert to request information about a flight. The information they can demand is in the Regulation which I quoted in the linked thread. It only applies to flights to or from the CTA and not to flights within Great Britain.
Are you sure about that Justiciar? TA 2000 Schedule 7 para 17 was amended by the Anti-terrorism, Crime and Security Act 2001 to permit the carding of passengers on any flight.
It now reads:
17. — (1) This paragraph applies to a ship or aircraft which—
(a) arrives or is expected to arrive in any place in the United Kingdom (whether from another place in the United Kingdom or from outside the United Kingdom), or
(b) leaves or is expected to leave the United Kingdom.
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