Measures to cut greenhouse gas emissions in the pre-budget report could mean extra costs for both air passengers and drivers.

The planned changes include a move to encourage the development of greener cars that use biofuels and switching air taxes from individual passengers to flights, from November 2009. The measure is expected to raise an extra £520m a year for the Treasury.

At present, all flight passengers from Britain incur air passenger duty of £10 for an economy flight; £20 for business class; £40 for an economy long-haul flight or £80 for business class. Though this is technically levied on airlines, most pass the extra cost down to the passenger.

The Treasury said it would consult in the new year on the exact system to replace APD, but one option is to use the weight of an aircraft at take-off to determine the charge per plane, said the Treasury.

Airlines could absorb the charge, but as with the current system are more likely to pass them on to passengers in the form of a “green supplement”.

The government will also close a loophole that exempts business passengers on private jets from green taxes.

Motorists could also face a steep hike in petrol prices under plans for “greener” fuel. Under the “renewable transport fuel obligations” scheme, petrol and diesel sold on forecourts will have to include 2.5% biofuel by April. This rises to 3.75% in 2009 and 5% in 2010.

Retailers who do not supply the fuel can opt out of the obligation by paying 15p for every litre of fuel from nonrenewable sources, but petrol companies that fail to meet targets face tough fines.

This could translate into higher prices for drivers, according to the Association of British Drivers). It said: “The cost of these changes and the research and development involved will inevitably make driving more expensive.”

Company car drivers who drive with free fuel when using their cars in a personal capacity will also pay more. The fixed figure on which the fuel benefits charge (FBC) is calculated will rise from £14,400 to £16,900. When combined with the 1% increase in CO2 ratings announced last year this means a 22% rise in the driver’s tax bill.

How much is paid depends on the efficiency of the car the tax bracket of the driver. A higher-rate taxpayer driving a two-litre Ford Focus C-Max that has a C02 rating of 192g per kilometre, will pay £1,325 under today’s rates but £1,555 when the changes take effect – £230 more. An employee with a more polluting car could pay up to £330 more, from £1,901 to £2,231.

Clive Fathers of accountants Grant Thornton said: “If drivers uses the car for private use less than for business it will cheaper to buy the fuel themselves.”

Drivers of “gas-guzzling” cars already face new penalties next year. The vehicle excise duty for the most polluting vehicles will jump from £300 to £400. Drivers of cars such as the Range Rover V8 and the Bentley Arnage will be affected.