Domestic and international flights are likely to be disrupted on Thursday when 15 unions covering all sections of employees, including pilots, cabin crew and ground staff, will go on a 24-hour nationwide strike to demand revocation of tax on free and concessional air travel passes.

"All our representations to the government have fallen on deaf ears. We have no option left but to resort to agitation for withdrawal of this unjust tax," Vaskar J Deka, regional secretary of the Air-India Employees' Guild, said in New Delhi.

The strike, which will begin at 0600 hours on February 20 and continue till 0600 hours on the next day, has been called by the National Action Committee of All Airline Employees, an umbrella body representing the 15 unions and federations including those of Air-India and Indian Airlines.

The final strike notice on Tuesday was served on civil aviation secretary K Roy Paul, in which the national action committee is understood to have sought a concrete assurance from the government on revocation of the tax.

The strike is likely to affect the flights of the two state-owned carriers, besides foreign and even private airlines as the engineering and ground handlers of A-I and IA also service the foreign carriers as well as the private domestic ones.

Deka said the national action committee expressed resentment over the government's decision 'to tax our free passages.'

While the railway employees were exempted from income tax on free passages through a notification issued on August last year, the airline employees 'who are entitled to the facility subject to availability are required to pay tax,' he said.

The committee spokesman George Abraham had earlier said the employees were being subjected to 30 per cent tax on the air tickets used by them.

He said the staffers of Air-India and Indian Airlines as well as Indian employees working with foreign carriers would participate in the day-long agitation.

The committee comprises, among others, the Air-India Employees' Guild, Indian Pilots' Guild (of A-I pilots), Indian Commercial Pilots' Association (of IA pilots), Air-India Cabin Crew Association, Air Corporations Employees' Union, All-India Forum of Foreign Employees, Federation of Domestic Airlines Employees, officers associations of IA and A-I, besides those of aircraft engineers.