Coincidentally I was reading up on this earlier today on FlyerTalk. Depending on the wind direction LAS uses either its N-S or E-W runways. The construction is on the N-S runways, so when they have to run traffic in that direction they reduce the frequency of takeoffs and landings. On Sunday afternoon they were using the E-W runways. I know that because I was looking out the window on approach and noticed we looped around town to the east and landed heading west. I am suspicious that airlines are using "construction delays" as an excuse more than is warranted— similar to how they claim "weather delays" at the drop of a hat because it excuses them from certain consequences with the DOT.