Is there a way to find out which flights will be 767 or 777 planes when planning air travel?

The airline will know. You may find it on their website. If they don't make the information available, then it's pretty hard to find out.

You can check the equipment used on previous flights with the same number on sites like FlightAware (http://www.flightaware.com). These will tell you which aircraft are most commonly used on a given flight. However, the airline will sometimes substitute other equipment at the last minute, depending on load and other factors.

Almost every website that has airline schedules includes the equipment type - Expedia, Orbitz, individual airline websites, Amadeus, etc.

Of course, that is simply the equipment that is scheduled. Airlines periodically change schedules. They also occasionally have unscheduled last-minute equipment changes due to maintenance, so there is always a slight chance that you'll end up on a different aircraft type than you planned.

You could find out when you book your flight if it's not listed you can always call the airline and just ask they tell you over the phone.

Try,

http://www.e-zbook.net