Relaxations of the rule allowing only one item of hand luggage aboard aircraft have been criticised as confusing but airport operator BAA said on Monday they offered passengers extra choice.
Travellers are now able to carry on board two pieces of hand baggage at 22 airports including Heathrow, Edinburgh and Manchester.
But 40 other airports, including Gatwick, are keeping the one bag limit, imposed last year after a terrorism alert.
Airlines are also adopting different policies, to the extent that EasyJet, which is maintaining the one bag limit, said there is "massive scope for customer confusion".
But BAA, which operates seven of the busiest UK airports, including Heathrow and Gatwick, said the different situation would not lead to confusion.
"Actually, it is quite simple," Tom Kelly, BAA communication director, told BBC radio.
"What passengers should do is talk to their airline. That was the position before the restrictions were introduced and that is now the position again.
"The good news today is that passengers actually can have a choice."
BAA will look to lift the baggage limit at Gatwick by the end of March after extra security lanes have been put in place, Kelly said.
Since last August, passengers have been limited to carrying one bag on board. Liquid containers could not be any bigger than 100 ml and had to be held in a clear, re-sealable plastic bag.
From Monday, passengers will be able to carry an additional briefcase or laptop-sized bag after the Department for Transport said it would ease the restrictions if extra security measures were introduced.
Restrictions will still apply on liquids.
British Airways has welcomed the change.
Robert Boyle, British Airways' commercial director, said: "It was a serious inconvenience for passengers and didn't make sense because the UK was the only country to impose the restrictions.
"Now we want to see the restrictions lifted at Gatwick in line with other major UK airports as quickly as possible."
Andy Harrison, easyJet's chief executive, said: "There is massive scope for customer confusion in an environment where UK airports are adopting different policies. The only way to maintain a simple and standard policy is to maintain our one bag policy."
