3D Blobular View of US Air Traffic 

Farecast et al

Not sure when to buy your airline tickets? Farecast (still in beta mode) expanded its database to over fifty cities last week. Enter the relevant cities and dates and it will predict when the fares will be cheapest (for RSS junkies it can even deliver a realtime ticker of fare predictions). Farecast claims an average 75% (and improving) accuracy level. While currently I use Orbitz, next time I may also try dohop.com which searches 660 traditional and low cost airlines worldwide. Can't decide between ORD or MDW? Get more airport info than you'll ever need at AirNav. Just need to pick someone up? FlightAware has the best (or at least, the most elaborate) flight tracker. Lastly, become convinced to always take the redeye by viewing some of the visualizations at Flight Patterns.

Airfare Predictions - Farecast

dohop.com

AirNav

FlightAware

Flight Patterns