I don’t think the plane actually did this?
must have been a long flight! 
Maybe they were looking for a soft spot in the weather.
It’s similar to this one:
http://flightaware.com/live/flight/EGF300/history/20060421/1648Z/KLGA/KLGA
…suspect what’s going on here is that there were two or more flights in the air simultaneously operating as EGF300. We’ve done some conceptual design work on heuristics to detect this and separate them when it happens. However, implementing it is taking a back seat to more pressing matters.
It happens a lot for designations like “AIR1” that might be designated for different flights in different regions.
Or maybe they did that to see if anyone onboard would notice.
The times listed for wheels-up DAL and down ELP showed a normal length flight. That why I questioned the plane doing it.
I posted a similar incident in another thread of this flight I was tracking http://flightaware.com/live/flight/WJA710 - dont think there were 2 WJA710 flights in the air at the same time but the track log http://flightaware.com/live/flight/WJA710/history/20060507/1414Z/CYVR/CYYZ/tracklog certainly shows some weird altitude changes in a short period of time.
woodytfc
And note the altitudes between 12:43 and 1:02… FL390 and FL320. One is an easterly altitude assignment, and one is westerly one.