Air Passenger Duty (APD) accounts for up to £6 out of every £10 spent on domestic flights, according to new research.
The A Fair Tax On Flying Campaign, which carried out the analysis, called for Chancellor Philip Hammond to use his upcoming Budget to cut APD by at least 50%.
Each passenger is charged APD on flights departing from UK airports, meaning they pay twice for domestic return trips.
The rate for a short haul economy class ticket is £13 per leg. The money goes to the Treasury.
A Fair Tax on Flying Campaign calculated what this charge is as a proportion of 18 air fares for domestic return flights booked on September 11 for travel on October 16 and 17.
The highest figure was 58% for London Stansted easyJet flights to Glasgow and Edinburgh, which both cost £45.
This was followed by Flybe flights from Southampton to Manchester (54% of £48), easyJet flights from Belfast International to Edinburgh (52% of £50) and Flybe flights from Cardiff to Edinburgh (46% of £56).
Henk van Klaveren, spokesman for the campaign, said: "This exorbitant tax on all short haul and long haul flights hurts the UK economy.
"It's a tax on trade and a tax on holidays. And this analysis shows that it is an unfair burden to business and leisure travellers making return flights within the UK.
"This damages connectivity, regional economies and the overall country. It is a definite brake on growing the benefits of tourism and business travel across the country.
"We are urging the Chancellor to decisively cut APD in the Budget by at least 50% across all bands of travel. This will help move the UK towards a more level playing field with some of our neighbouring economies."
Passengers carried on flights leaving from airports in the Scottish Highlands and Islands region are exempt from APD.