Airbus (EADSY) shares slipped Monday as the aircraft manufacturer worked through what it's calling one of the broadest emergency actions in company history—a software glitch affecting its A320 family that's been linked to solar flare vulnerabilities discovered during a recent JetBlue mid-air incident.

Here's the situation: Airbus fleets are returning toward normal operations after the planemaker pushed through software changes faster than expected. Airlines across multiple regions completed rapid retrofits following the discovery of the flaw, which affects nose-angle control functions. Most of the roughly 6,000 affected A320-family jets have now been modified, with fewer than 100 still requiring work.

The fix itself was relatively straightforward—reverting to an earlier version of the software that controls nose-angle functions. But the rollout wasn't without hiccups. Some airlines faced delays due to limited availability of data loaders needed for the update. EasyJet and Wizz Air managed to complete modifications without canceling flights, while JetBlue planned to cancel about 20 flights Monday and Avianca paused bookings until Dec. 8.

The recall initially created uncertainty as operators worked to identify which aircraft required updates. Engineers later narrowed down the list, and several carriers said the number of affected jets was lower than initially estimated—a rare bit of good news in an otherwise chaotic situation.

The bigger concern? Older A320-family jets that will require replacement computers rather than a simple software reset, and that's happening amid global chip shortages. Those questions remain unanswered as Airbus CEO Guillaume Faury issued a public apology while the company faces heightened global safety scrutiny.

At the time of writing, Airbus shares are trading 2.35% lower at $56.39.