The ban affects nine international airlines with direct flights to the US. The UK's restrictions apply to eight foreign carriers and six British airlines.
A ban on laptops in plane cabins bound for the United States from some cities could deal a blow to the big, fast-growing Gulf airlines, which depend on business-class flyers stopping over in places like Dubai or Doha for far-flung destinations, Gulf airlines and experts say.
The US announced the new measures on Tuesday and Britfain followed suit, prompted by reports that militant groups want to smuggle explosive devices in electronic gadgets.
The US restrictions apply to flights originating from 10 airports in countries including the United Arab Emirates, Qatar and Turkey, meaning they will impact major international carriers including Emirates, Qatar Airways and Turkish Airlines, but not US-based carriers, none of which fly to those airports.
The British restrictions do not include the UAE or Qatar but will affect Turkish Airlines and UK-based carriers including British Airways, easyJet and Monarch. EasyJet said that the UK restrictions apply from Wednesday.
The restrictions are especially unfortunate for the Gulf carriers, since a large proportion of their revenue comes from passengers who change planes at their hubs and have other options that avoid affected airports.
Emirates, Etihad and Qatar Airways have been battling lobbying from major US carriers which have accused them of receiving unfair subsidies, charges the Gulf carriers deny.
Tim Clark, president of Emirates, the world's largest long-haul carrier, questioned why his airline's hub was on the list.
"Yes, this new security measure is disruptive and operationally challenging in several regards, but I am optimistic we'll get through this."
Travellers across the Middle East expressed frustration on Wednesday at the ban that has sparked confusion and speculation.
At the Tunis airport, a passenger flying to Canada via London said that he was confused by the new measure.
"I mind because I need my laptop or my iPad. It's a personal thing. Why do I have to put them in hold?" said Riadh, 33, adding he now feared they would be damaged or stolen.
This has no impact on American Airlines customers. We'd love to fly you to all the amazing places we go.— American Airlines (@AmericanAir) March 21, 2017
That's precisely the point. Thus proving the absurdity + bias of this decision. So, no. I'd rather transit somewhere than give you a dime. https://t.co/7bf48fi2f6— Mohamed El Dahshan (@eldahshan) March 21, 2017
Business travellers paying top prices for flat beds and other perks may balk at stowing their laptops on long trips.
According to the Washington DC-based Global Business Travel Association (GBTA), around 49 percent of business travellers prefer to stay connected and get work done while flying.
The GBTA added that many companies advise staff travelling on business to keep their devices close because they may contain sensitive information.
Liberum analyst Gerald Khoo said that the restrictions could potentially benefit European carriers such as British Airways and Iberia parent company IAG, Air France-KLM and Lufthansa, which offer alternative routes between the US and Asia, Africa or the Middle East.
A day after the new restrictions, some rival airlines were already trying to attract business by saying that they are not affected by the new rules.