The risk is if too much of the industry fails, it could lose critical mass and completely collapse. Not just the airlines, but the entire support structure. The airline industry is critical infrastructure - even a partial collapse could have catastrophic cascading consequences to other parts of the economy.
No, the airline industry is not alone, but it'll be a whole lot harder to recreate a viable airline industry than to - for example - open new restaurants to replace all those that went under due to the lockdown.