Low cost airline Ryanair's dispute with its pilots remained deadlocked last night after seven of them failed to accept terms for training on its new craft.

The carrier will complete the replacement of its fleet of Boeing 737-200s with 737-800s by the autumn.

Most Irish pilots, including the seven whose deadlines ran out last night, are refusing to retrain to fly the new fleet because they object to the conditions on which the airline is offering training.

Ryanair wants them to return the €15,000 cost of the programme if they leave within five years, or if the company is forced to negotiate with any pilots' trade union during that period. It also wants Irish pilots to drop court cases they have taken against the company.

Last night the deadline for seven senior Dublin-based flyers to accept the latest offer ran out. It is understood they wrote to Ryanair refusing to either accept or reject the offer, and seeking clarification of a number of points.

An airline spokeswoman would not comment beyond saying that the pilots had until close of business last night to accept the offer.

Ryanair chief executive, Michael O'Leary, recently warned that the pilots would lose their jobs if they are unable to fly the new craft once they are completely phased in next autumn.

However, he also said Ryanair would continue to offer them the opportunity to retrain to fly the 737-800s for as long as possible.

Last night's development is the latest round in a long drawn out dispute between the airline and its Irish-based fliers. The pilots have already rejected a number of company offers to retrain.

One of the pilots' main sticking points is the demand that they repay their training costs if the airline is forced to engage in collective bargaining with any pilots' trade union. Ryanair does not recognise unions.

The pilots argue that if their colleagues in other countries succeed in forcing the airline to deal with a trade union, then they will have to repay the money.

Sixty-four Irish-based pilots have taken High Court proceedings claiming that Ryanair's refusal to negotiate with a union is a breach of their constitutional rights. They are members of the Irish Airline Pilots' Association (Ialpa), an affiliate of the trade union, Impact.

They are also opposed to the repayment terms. Airlines generally seek to recoup training costs if pilots leave within a short space of time, but the amount is reduced over the period of their service. Ryanair staff argue that under the offer's current terms, they would have to repay the full amount whether they leave a day after completing training or four years and 11 months later. They also claim they would have to repay it if for medical reasons they were deemed unfit to continue flying.

Ialpa said last night it could not comment on the latest development because Ryanair did not engage in collective bargaining, and the issue thus only involved the pilots and the airline.

Separately, Ryanair said yesterday that its company secretary, Jim Callaghan, had sold over €100,000 worth of shares in the company.