As many as 100,000 people have written to MPs to urge a review of the "too high" air passenger duty (APD) airport departure tax.
The figure was announced by campaign group A Fair Tax on Flying.
The group also said 75 MPs had signed a parliamentary early day motion calling for more Treasury research into APD which was increased by around 8% this year.
One of those who has signed is former Liberal Democrat leader Charles Kennedy.
He said: "I hope that the Government will listen to the thousands of people who have written to them on this issue, and undertake a comprehensive impact assessment to establish the true economic consequences of the increase of APD."
Virgin Atlantic has calculated that this year's rise in APD will cost passengers an estimated £600 million this summer.
Constituents supporting the APD campaign have contacted MPs by email via A Fair Tax on Flying's website.
The campaign group said Prime Minister David Cameron has received around 200 emails, while Cabinet members in total had received more than 5,700.
One air passenger, Alan Hunn from Crawley in West Sussex, who emailed his MP, said: "The ever-increasing taxes we pay on air passenger tickets is restricting the number of times I can travel to see my family.
"On the outbound flight from Heathrow, I am now paying just over £120 in taxes, and yet the return tax from Nairobi is only £9.50."