Boeing’s 737 Max plane has been banned from the UK and the rest of the European Union following the Ethiopian Airlines disaster, which killed 157 people including nine Britons.
The Civil Aviation Authority (CAA) said its ruling was “a precautionary measure” and would remain in place “until further notice”.
The European Union Aviation Safety Agency later announced a ban which covers the entire bloc.
But the Federal Aviation Administration (FAA) on Tuesday said that its review had so far provided “no basis to order grounding the aircraft”, nor had other civil aviation authorities provided data to warrant action.
A pair of Turkish Airlines 737 Max 8 services to London Gatwick and Birmingham returned to Istanbul mid-flight.
A number of other countries around the world have banned the 737 Max 8, which was the model involved when Ethiopian Airlines flight ET302 crashed shortly after taking off from Addis Ababa on Sunday morning.
This includes Austria, China, Australia, Singapore, Oman and Indonesia, but flights are continuing in the US and Canada.
Tui Airways has the only five 737 Max 8 aircraft operated by a UK-based airline, and confirmed the planes have been grounded following the CAA’s decision.
A Tui UK spokesman said its customers will “travel on holiday as planned on other aircraft”.
Scandinavian airline Norwegian, which is the other major operator of 737 Max 8 aircraft in the UK, apologised to customers “who will be affected by temporary cancellations and delays”.
Brian Strutton, general secretary of pilots’ union Balpa, welcomed the CAA’s ruling.
“Safety must come first,” he said.
“It is too early to know the cause of the latest crash and it is vital that air accident investigators carry out a thorough investigation to identify the cause so that measures to prevent future accidents can be put in place.”
But the FAA said in a statement that its review so far had showed “no systematic performance issues” and provided “no basis to order grounding the aircraft”.
Acting FAA Administrator Daniel K Elwell said: “The FAA continues to review extensively all available data and aggregate safety performance from operators and pilots of the Boeing 737 Max.
“Thus far, our review shows no systemic performance issues and provides no basis to order grounding the aircraft. Nor have other civil aviation authorities provided data to us that would warrant action.
“In the course of our urgent review of data on the Ethiopian Airlines Flight 302 crash, if any issues affecting the continued airworthiness of the aircraft are identified, the FAA will take immediate and appropriate action.”
The Ethiopian Airlines crash was the second deadly incident involving the new model of Boeing passenger jet in less than five months, prompting concerns over its safety.
Some 189 people died when a Lion Air flight crashed into the Java Sea shortly after taking off from Jakarta on October 29.
Max aircraft feature an automated system which forces the plane’s nose down when it detects there is a danger of stalling.
A report into the Lion Air disaster found the system repeatedly forced the plane’s nose down despite it not stalling.
US President Donald Trump tweeted that planes are “becoming far too complex to fly”.
Boeing said in a statement it has “full confidence in the safety of the 737 Max”.
It went on: “The United States Federal Aviation Administration (FAA) is not mandating any further action at this time, and based on the information currently available, we do not have any basis to issue new guidance to operators.”
The passengers killed in Sunday’s crash came from 35 nations, including 32 from Kenya and 18 from Canada.
British victims included Joanna Toole, a United Nations worker from Devon, along with 55-year-old Joseph Waithaka, polar tourism expert Sarah Auffret, Sahra Hassan Said and Nasrudin Abdulkadir, a mother and son with dual Somali-British citizenship, and Sam Pegram, a 25-year-old from Lancashire.
Manuel Barange, director of Fisheries and Aquaculture at the UN Food and Agriculture Organization, said Ms Toole was a “remarkable” woman.
He added: “As a worker she had an amazing passion for what she wanted to do, she was only 36 and she had achieved so much.
“The fact she was leading global guidelines at that age was remarkable.”
Dr Barange said that the guidelines Ms Toole had been spearheading on reducing marine litter would be dedicated to her.