This website allows you to track all airplanes currently in the air. Just zoom the map into your area and you'll see the planes. Click on one and you'll get the details.
When we came home from Phoenix a month ago, we saw some other commercial jets very close to us. First we met one, going opposite direction to us. Looked to be maybe 1/2 mile to 1 mile below us and even looked closer than that horizontally (although I suspect it was likely at least a mile away?). When you're both going about 500 mph and meeting, you don't get much of a look!
Then only about 1/2 hour later one crossed in front of and below us, similar distance. Man, that looks fast!
__________________
1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)
