Prime Minister David Cameron has said it is "more likely than not" that the plane was brought down by a terrorist bomb.
More than 20 flights are set to be operated from Sharm to the UK tomorrow amid tightened security, including a ban on airlines carrying hold luggage.
Anything that cannot be taken on board under standard hand luggage regulations will be brought back to the UK "by a Government agency and will be returned to you by courier", easyJet told passengers. "We anticipate that to be within the next seven days."
EasyJet and Thomson Airways announced that they will operate nine flights each to the UK tomorrow, including a number of "rescue flights".
Monarch published details of five flights from the Red Sea resort.
Despite the announcements from the airlines, Downing Street would only confirm that it was "making good progress" on enabling repatriation flights.
A spokesman said: "Our utmost priority is to make sure that we have all the right measures in place to ensure British citizens can return safely to the UK."
But a Monarch spokeswoman insisted: "Our flights are going tomorrow. They are not (just) planned, they are definitely happening."
Speaking after talks with Mr Cameron at 10 Downing Street, Egyptian President Abdel Fatah al-Sisi said he believed there was a "good mutual understanding" and that Cairo was "completely ready to co-operate with all of our friends" on ensuring the safety of foreign tourists.
He said he hoped normality would be restored "in the soonest time possible".
Mr Sisi told reporters that British experts had looked at security in Egyptian airports 10 months ago, at the request of London, and found then that they were "good enough".
Speaking alongside Mr Sisi at Number 10, Mr Cameron said the two countries were "working intensively together in a spirit of close co-operation" and that it was "in our mutual interest to address this and get back to normal as soon as possible".
Some British tourists in Sharm have clashed with hotel staff as tensions rise over delayed flights.
Holidaymakers reacted angrily to being charged more money to stay in the resort's hotels.
Emma Smyth, who is staying in the Aqua Blu hotel, about 12 miles from the airport, said the frustrations were starting to boil over.
"Because English people are frustrated and upset, they are taking it out on the staff here, which is not fair," she said.
"One English family, who are obviously upset and concerned, have asked the hotel if they can stay on. The hotel have set a charge and the tourists cannot understand why they are being charged."They said they should be allowed to stay and, with that, one man grabbed one of the managers - they ripped his shirt, ripped his name-badge off."
Downing Street confirmed that a team of British experts had gone to Sharm el-Sheikh about 10 months ago as part of a long-term approach to assessing security arrangements at the airport.
Mr Cameron's official spokeswoman said the UK had received "good co-operation" from the Egyptian authorities, who addressed concerns raised at that point.
Wednesday's decision to ground flights was a response to "the evolving nature of the threat" rather than an indication that the UK was not satisfied with the measures taken following the earlier visit.
The spokeswoman declined to discuss the precise nature of the security concerns. Asked whether the UK was unhappy with background checks being carried out on baggage handlers, she replied: "Following on from our assessments yesterday, there are a range of options for how we might address security."
She did not rule out the possibility of British personnel directly providing security at the airport, saying only: "There are a range of options being considered."Britain was keen to ensure the security of passengers at every stage as they pass through the airport and wanted to be confident that planes remained secure between their arrival and departure from the airport.