A bit of web-surfing by poor old DonDiego reveals the following:
__SouthWest Airlines (SWA) outsources lots of maintenance, as do most airlines nowadays. (
n.b."outsourcing" means they contract with another firm; most outsourcing remains in the USA.)
__The National Transportation Safety Board (NTSB) claims the most recent airframe inspection on the 737 on which the roof tore back was accomplished in March 2010 in Dallas, TX, . . . also home of the despicable Dallas Cowboys NFL Football Franchise. In fact, the NTSB said the jet in question had had all required maintenance work and inspections done, its papers were in order and there were no outstanding maintenance items.
__SWA claims 85% of its aircraft maintenance is done within the USA. This includes all electronics/controls/on-board equipment/etc. and all engine work; the Salvadorean facility performs airframe work.
__The aircraft on which the roof tore back is one of SWA's oldest aircraft. The fault for not "catching" this weakness of the 737 lies mostly with Boeing; the inspection manuals did not require special inspection of the joint which tore; they will now, as cracks have been detected on many aircraft after the incident.
DonDiego recognizes nothing stated above would've comforted the families of the victims had there been any victims in the incident cited.
One can read the Transport Workers Union (TWU) report referenced in the FoxNews YouTube above at TWU Local 514 .

DonDiego would feel better if all maintenance was performed in the good old USA by 'mericans, . . . although he doesn't really
know that foreign work is inferior.
Nonetheless he recognizes the air passenger transport business is difficult; historically most airlines in the USA lose money until they go bankrupt and merge or sell their assets to another airline which then continues to lose more money. SWA has been an exception.
The romance of owning an airline like that of Howard Hughes is no more. Most airlines now comprise a corporate entity which hires and manages personnel, leases its office space, leases its aircraft, leases its gates, leases its maintenance facilities (if any), outsources its baggage handling, outsources its food handling/processing, and outsources its maintenance.
DonDiego says: "Happy Flying !"