One of our biggest worries on days when we travel by air is how the weather's going to be.When you wake up at home and see sunny skies and calm winds, you assume it's going to be a great day for flying. However, that's not always the case, and many parts of the country are experiencing strong winds that'll either make your flight cross-country super fast, or one of the slowest you've experienced. The jet stream, the current of air thousands of feet above us that storms follow, is extremely strong. Wind speeds in the air between 30,000 feet and 40,000 feet have been clocked between 200 and 250 mph at observation sites across the Northeast on Tuesday. That's the altitude that most commercial airline planes fly. The strong winds translate to an extremely good tail wind for planes heading from the west coast to cities east. The Washington Post reported some planes reaching speeds of 800 mph heading east. The typical cruising speed for planes is between 500 and 550 mph heading east. However, when flying west, planes are facing incredible headwinds. Several planes we tracked heading west from Boston struggled to reach speeds of 400 mph, significantly slower than typical speeds. The headwinds can even force some smaller planes to have to make unscheduled landings at airports across the Midwest to refuel. One American Airlines plane bound for Los Angeles was forced to make a pit stop in Minneapolis. So if you're planning to pick up family on a flight that left the west coast on time, expect them to be a bit early. If you're heading west on a flight, you may want to order that second beverage.