Air passengers are having to pay an increased airport tax from Thursday, even if they bought their tickets before the announcement in December.
Despite warnings it would cause chaos at airports, the change has not resulted in too many delays at the UK's airports, with most reporting business as usual.
BBC correspondents met many passengers at Birmingham, Liverpool and Luton airports who expressed irritation at the extra fee, while others were welcoming.
Airlines are threatening to sue the government over the tax increase
Passengers at Birmingham International Airport seemed well informed about the increase in air passenger duty, although few thought it fair.
Anne and Terry Taylor from Coventry chose to book their holiday to the Egyptian resort of Sharm El Sheikh with First Choice because the company agreed to absorb the cost of the new tax.
Mrs Taylor said: "We booked on Christmas Eve, so we knew about the tax. I think it's disgraceful.
"When you book a holiday it should be a legally binding contract, the price should be fixed, with no extra charges, which is why we booked with someone who had absorbed the cost."
Kamal Paul, 30, from Kettering, said he was pleased that Uzbekistan Airlines had waived the fee.
Mr Paul, who had brought relatives to the airport for their flights to India, said: "People who have booked in advance should not have to pay more.
"Some people's budgets are difficult and they can't afford to pay any more.
"£40 or £80 is an extra spending spree on holiday, particularly in India."
Jeevan Kaur, 17, from Kettering, was flying to Amritsar in northern India. She said she has flown to India about once a year since she was a child.
She said she appreciated the environmental impact of this but thought the cost should be paid by the airline, not the passenger.
"The flights are expensive as it is, you should just have to pay upfront once.
"My flight has been delayed by eight hours, which I won't get any money back for, so why should I pay an extra £40 to the airline?"
Apart from the usual delays, and a few passengers who missed their flights because of hold-ups on the roads, the airport was as quiet and organised as any other weekday.
LIVERPOOL JOHN LENNON AIRPORT
Easyjet has decided to pass the tax burden onto its customers
Would the man who this airport is named after have approved of today's rise in duty? The lyrics to Taxman by The Beatles are scathing. And John Lennon, who reportedly liked George Harrison's song, may have felt this was another money-grabbing exercise.
But as a singer with a social conscience, he may have been up on the green platform himself if he was alive today.
That split in viewpoint is reflected among many of the passengers here today. Janice Beasley, from Nantwich in Cheshire, is flying to her holiday home in Cork. "Taxes are high enough already," she said.
"We do need to worry about the environment. But rather than mess with the taxes they should just make the fares themselves more realistic."
Felicia McBride, on her way to Belfast from the Wirral, thought the rise in duty was a good idea "because of the pollution".
She added: "I'm happy to pay it as long as it goes on environmental projects. But they didn't really give us much notice that it was going up."
Any disruption here is not obvious. The queues are the normal length and passengers are moving steadily forward, but there have been hiccups.
Ryanair had said that they would automatically take the extra duty from the credit cards of people who'd already booked. But today, some customers were being sent to the company's customer services desk to pay the extra cash.
Ross Cooper, from Preston, is travelling on Easyjet with his seven-a-side football team-mates to watch Real Madrid play.
He said: "It's an absolute joke. I booked and paid my money two months ago. Last week I got an email final reminder. It was the first I'd heard about it. I had to go and beg a fiver off all my mates."
LUTON INTERNATIONAL AIRPORT
Most passengers seemed aware of the increase in passenger duty
All seems to be going smoothly at Luton Airport, according to the BBC's Colette McBeth.
Easyjet officials are walking around the airport dressed as tax collectors but the airline says most passengers paid the increase in advance over the internet or the phone after being informed via email.
There are signs all over the terminal informing passengers about the new tax, and those who did not know about it or did not pay in advance are being allowed to pay at the airport.
David and Lydia, who were travelling with two children, had to pay £30 extra to go on a skiing holiday.
David said: "It's quite a lot to pay but the flights were quite cheap though, so we didn't expect Easyjet to pay for it."
When asked if they minded paying the tax, which is meant to help the environment, he said: "It depends what the tax will be used for. If it is earmarked for green issues then we don't mind very much".