Busy last few days in aviation, with several major developments that effect the CLT. The highlights:

• American Airlines ordered a bunch of jets from Airbus and Boeing. What’s that all about? Simple: AA has an old fleet — lots of 767-200s and MD80s plus Boeing 757s used on relatively short routes — that are not very fuel efficient. This order address will allow the airline to replace those older planes.

CLT/US Airways impact: BTDT. You’ll hear a lot about the need for other airlines to follow American’ lead and to modernize their fleets. This is about replacing circa 1990 aircraft (MD80s, early A320s, 737-300s, 737-400s, 737-500s, 757s if used on short routes) with the more efficient aircraft available today. US Airways already has partially done this and has orders in place to replace its remaining older narrowbodies with 70 new A320s and A321 between now and the end of 2015.

Oh, while this is nice and all for American Airlines, this isn’t the key for its turnaround. (AA is expected to be the only large US Airlines to lose money in the second quarter.) Fixing American depends upon reducing its labor costs. That’s going to be tough, as it has a strained relationship with virtually all of its unions, who think their members are underpaid. Fix American, and then a merger with US Airways may be possible.

• The DOT gave tentative approval to the Delta/US Airways slot swap on Thursday. The expectation is the deal will close before the end of the year. The actual trading of slots will happen in two phases. Best guess for dates on that is April or May 2012 and with the second wave after Labor Day or possible a little later.

CLT impact: Does US Airways use the DCA slots it gains to serve places it currently doesn’t fly to? If so, do these places also get flights from Charlotte? This is the next best chance for US Airwatys to add new domestic routes from CLT. And on the Delta side, will they resume CLT-LaGuardia flights? And where do the aircraft for Delta’s increased LGA service come from? (Hint: Memphis and Cincinnati are possibilities.)

• The children in the US Airline Pilots Association — US Airway’s pilots union — are throwing safety allegations at the company. This would be a labor contract negotiating tactic. Also expect for them to oppose the slot swap though its clearly in their interest.

Continued impact: Expect this sort of noise to continue until a new pilots contract is reached. Negotiations are in a holding pattern until the underlying US Airways/America West pilot seniority integration issue is addressed in court or otherwise resolved. Good luck on that.

• Southwest Airlines put out their January and February schedules today. It includes some major route cuts from Philly to Manchester, NH, Providence, RI, and Pittsburgh, all of which are four daily, are being dropped. So is the daily Philadelphia – Jacksonville, FL flight. Philly – Boston, currently at eight flights a day, will be down to five flights a day by February. So a nice win for US Airways there.

CLT impact: Southwest still has about 40 flights a day from PHL but they are almost all to the airlines major stations or places in Florida. (The exceptions are Boston and Raleigh.) So yes, Southwest is a hub-and-spoke carrier on the East Coast. Accept it. When they get here via the AirTran merger, Southwest’s CLT offerings will be limited in scope (say 8 to 16 flights) and quite predictable.

Update: Dug out the numbers. Southwest had 71 flights a day from Philadelphia in the summer of 2008 and 67 in the summer of 2009. They’ll be down to 38 flights a day from Philly come February. Wow.