When is the best time to buy an airplane ticket?

I think that all airlines have their own matrix for when they discount their fares. The best thing to do is to check several airlines often and when you find that an airling has a paticularly low rate just grab it. We just did this for a trip this spring. My husband won’t fly coach so we have to keep checking until we find a deal on business class. We got a ticket on United for $900 that was $3000 to $5000 on the other airlines. We just happened to be watching at the right time.

Analysts have studied the patterns and say Tuesday, 3 p.m. EST, is the time to buy the cheapest flight tickets domestically.

that wouldnt work due to being at work at that time :(. I checked flights today against prices from a few days ago and they were the same.