Brokers have 30 days to negotiate adequate third-party cover for aircraft.
Insurance underwriters recently limited third-party cover to $50m (£34m) per aircraft, following the terrorist attacks in the US.
Aircraft must have $700m (£476m) of third-party cover in order to be legally allowed to fly, so the government has struck a deal with airlines and agreed to pay the cost of maintaining airlines' insurance cover for 30 days to prevent a threatened grounding of passenger aircraft.
This will ensure airlines have enough third-party cover to ensure they do not breach aircraft leasing regulations.
A spokesman for Willis said it had been in negotiations with insurers: “We are confident there will be cover in place by the end of the 30-day period.”
The company has 240 employees and flew to Paris and the Channel Islands.