Lufthansa and its sister airlines, including SWISS and Austrian Airlines, are burning through one million euros from their cash reserve every hour.

CEO Carsten Spohr addressed staff Wednesday in a video message, telling them the coronavirus pandemic represented "the greatest challenge in our history" and that Lufthansa is "fighting" for its future .

In total, we therefore lose one million euros of our liquidity reserve every hour - day and night, week after week and probably month after month," Spohr said.

The airline group, which owns national carriers in Germany, Switzerland, Austria and Belgium began the crisis with financial reserves of more than four billion euros, but the group was only posting a "fraction of the revenues" it normally earns.

He said that receiving government support is the only way it can survive the coronavirus crisis. CNN has confirmed Spohr's comments to employees.

Lufthansa Group (DLAKY) currently carries fewer than 3,000 passengers per day. It usually flies around 350,000 passengers a day,