4th of July travel forecast: How to avoid traffic and what to know before flying

Record-high travel numbers are possible this Fourth of July holiday.

Here's what to know before you head to the airport or hit the highway:

Air travel

According to Expedia, Saturday, June 29, will be the busiest day in the airports before the Fourth of July.

Wednesday, July 3, is the busiest day to leave for vacation and Sunday, July 7, and Monday, July 8, are the busiest days to fly home, according to Hopper.

United Airlines said it expects to fly a record 5 million passengers from Friday, June 28, to Monday, July 8. United predicts June 29 and July 7 will be its busiest days.

American Airlines anticipates its busiest Fourth of July ever, with more than 7.2 million customers across 70,000 flights -- up 8% from last year.

Delta Air Lines said it's forecasting 5.8 million customers between June 28 and July 7 -- up 6% from last year.

AAA said domestic airfare is 2% cheaper this year compared to last year, with the average price of a domestic round-trip ticket at $800.

If you're looking to book a last-minute getaway, Hopper recommends leaving on Thursday, July 4, and returning on Tuesday, July 9.

The most-searched U.S. destinations are New York City, Seattle, Los Angeles, Miami and Orlando, Florida, according to Hopper.

The busiest U.S. airports are expected to be Hartsfield-Jackson Atlanta International Airport, Dallas Fort Worth International Airport, Denver International Airport and Chicago O'Hare International Airport, according to Hopper.

Road travel

A record 60.6 million people are expected to hit the road for the Fourth of July -- up 2.8 million travelers compared to last year, according to AAA.

The worst traffic is expected on July 3 and July 7, according to transportation analytics company INRIX. But if you still need to drive on those days, the best time on July 3 is before noon and the best time on July 7 is before 11 a.m.

Monday, July 1, is the best day to be on the roads, according to INRIX.

The highest demand for rental cars is in Dallas, Denver, Salt Lake City, Los Angeles and San Francisco, AAA said, citing its rental partner, Hertz. The busiest days to get a rental car will be June 28, June 29 and July 3.