The months-long battle between Ryanair boss Mr Michael O'Leary and EU regulators comes to a head tomorrow when Brussels looks set to order the low-cost carrier to repay millions of euros in subsidies.
Mr O'Leary's sees Brussels bureaucracy threatening the no-frills air industry in Europe, which has revolutionised travel by bringing low ticket prices to millions and taking on the sector's giants.
For European Transport Commissione, Mr Loyola de Palacio, Ryanair and other low-cost operators must respect the rules of the free market, meaning that there must be no unfair subsidies paid to them by state-owned airports at taxpayers' expense.
In last-ditch lobbying, Ryanair urged the Commission to delay for a month its ruling on whether Belgian regional airport Charleroi gave it illegal aid in the form of cut-price landing fees, ground handling charges and marketing costs.
Ryanair has also threatened to unleash a flood of litigation against rival carriers if the EU executive finds against it.
"This decision will result in higher fares for consumers by forcing the low fares airlines generally to pay higher costs, and these costs will be reflected in higher fares for the travelling public," the group.
But unless the Commission changes its mind at the last minute, EU officials expect it to rule tomorrow. The EU executive has estimated the sum to be repaid at between €2 million and €7 million euros, EU sources say.