The article does discuss union collective bargaining agreements and labor cost structure in several sections.
> Labor costs might seem variable, but they’re actually not: pilot, flight attendant, and mechanic compensation in the United States is governed by the Railway Labor Act of 1926 (which was extended to airlines in 1936), which stipulates that collective bargaining agreements don’t actually expire but rather remain in force until they’re replaced. So even your wage bill is more or less fixed over multi-year horizons.
> Chapter 11 bankruptcy protection—which allows a company to continue operating while it restructures its debts under court supervision—is practically the only mechanism by which an airline can renegotiate its rigid cost structure, from aircraft leases to collective bargaining agreements. Oftentimes this renegotiation takes on a rather predatory character. When United Airlines filed for bankruptcy in 2002 in the aftermath of the September 11th attacks, it terminated its pension plan...
> So Chapter 11 is a relief valve for airlines struggling under the weight of their fixed costs; but it doesn’t really do much to help the system as a whole. For airlines, bankruptcy rarely culminates with liquidation; airlines that emerge from bankruptcy proceedings, having voided pension obligations and rejected aircraft leases, can operate at a fundamentally lower cost basis than their competitors. So bankruptcy doesn’t really restore the industry to a competitive equilibrium that can cover the cost of capital: it resets the floor at a lower level, from which a new round of ruinous competition can begin.