LONDON (Bloomberg) — British Airways chief executive officer Willie Walsh must decide whether to stand his ground against cabin crew workers and ride out a strike that may cost the equivalent of 75 percent of projected annual profit.

The Unite union, which yesterday called four five-day walkouts starting May 18, says the carrier must reinstate free travel and take back fired workers to win consideration for a pay plan that's "an improvement" on previous offers. British Airways said the pay offer is "very fair".

The strike may cost £150 million ($223 million), including business lost on the single days between walkouts, based on the £45 million expense of seven days of stoppages in March. Analysts estimates are for a £205 million operating profit in the fiscal year that began April 1.

"As a hit to profits it's painful, but as a drain on cash it's manageable," said Douglas McNeill at Charles Stanley Securities in London. "It would be treated as a one-off, so I think investors would be tolerant."

BA has a cash balance of £1.6 billion, chief financial officer Keith Williams said in February.

British Airways fell 1.8 percent to close at 200 pence in London trading. The stock has declined about five percent since February 19, the last day of trading before Unite announced the first strike.

Airline shares have also been hurt by repeated shutdowns of the Europe's airspace following the eruption of Iceland's Eyjafjallajökull volcano on April 14. Traffic at British Airways fell 22 percent last month, with dust disruption likely to cost the company about £100 million, according to Williams.

About 81 percent of cabin crew voting in a ballot on the latest pay offer followed Unite's advice to reject the deal, the union said last week. British Airways made no new proposals over the weekend, the union said yesterday, adding that there can be no agreement "while management victimises trade unionists and uses disciplinary procedures in a witch hunt".

Unite is open to further talks, spokeswoman Pauline Doyle said yesterday in an e-mail. "Our door remains open," she said. London-based British Airways, Europe's third-biggest carrier, said in a statement yesterday that it is "saddened but not surprised" by the new strike call.

The British Airline Pilots' Association said yesterday that it would work normally through any strike, adding that "it is for all groups within BA to make a contribution". The labour group last year reached a deal with BA which it says gives the company annual savings of £25 million.

Walsh cut cabin crew staffing levels in November without union approval in an effort to save £127 million after the global recession hurt demand for air travel. While business trips have picked up in recent months, BA may suffer a record £600 million pretax loss for the year ended March 31.

The company is due to report results on May 21.

Andy Harrison, CEO at EasyJet Plc, Europe's second-largest discount carrier, said on a conference call with reporters yesterday that his airline may benefit by a "few million pounds" from the BA strike as customers switch flights.

"Things are improving, but it's important that all airlines come out of this crisis more efficient than when they went into it," said Stephen Furlong, an analyst at Davy Stockbrokers in Dublin with an "outperform" rating on BA stock. "BA crews are still less efficient compared with many other airlines."