Negotiations with striking pilots broke off early yesterday morning and were not expected to resume until tomorrow. Since it will take 48 hours to return Air France flights to normal, even a Monday settlement would leave thousands of long-distance fans - chiefly from South and North America and Asia - scrambling to switch to other airlines and other European destinations.
Hence Mr Jospin's decision to intervene. He said yesterday that the government would "play a role in the coming hours", while respecting the independence of the state-owned airline.
The embarrassment and anger of the French government is all the more acute because no large points of principle remain in dispute between the six pilots' unions and the airline. Negotiations broke down, or broke off, at 7.30am yesterday, when the largest union, with 60 per cent of the Air France pilots, refused pleas to continue bargaining throughout the day - or throughout the weekend if necessary.
The outline of a possible settlement has been on the table since Thursday: only the small print and precise timetable of a deal appear to remain at issue. It seems, however, that the main union, the Societe Nationale de Pilotes de Ligne, having softened its tone on Thursday, has been forced to return to a tougher line by its rank-and-file members.
If the strike continues into the World Cup, Air France has promised to draft in its executives to fly planes, or to charter aircraft to meet its commitment to fly the 32 competing squads between the 10 host towns. Once they arrive in France, the absence of internal flights - only a quarter were operating yesterday - will inconvenience a minority of the wealthier fans.
It will also make TGV rail services even more crowded than usual. A minority of train drivers is also threatening to strike on Wednesday but this is not expected to cause much disruption.
The main damage caused by the air strike will not be to the World Cup itself but to the economic future of Air France, and to the image the French government wished to project of a can-do, modern nation.
The dispute arises from the need to prepare Air France for freer European competition in air travel and for a partial privatisation. The management wants the pilots - average salary pounds 75,000, a fifth more than British Airways - to accept a 15 per cent cut over three years. In return, pilots would receive shares in the part-privatised company.
Both sides agreed last week on a formula which would allow pilots to accept the shares but have their pay restored to their existing levels in a few years' time. A deal along these lines is still likely.