For the second consecutive year, the outlook for summer travel continues to brighten with more than three in five U.S. adults (64%), or an estimated 154 million Americans, planning on taking at least one trip for leisure purposes during the next six months, according to the U.S. Travel Association’s quarterly report “travelhorizons,” which is based on a survey of 2,200 U.S. adults taken in April 2012 and is in partnership with MMGY Global.

Overall, the percentage of Americans planning to travel is up from 61% in April 2011 and from 56% in April 2010, according to the travelhorizons report.

Business travel is also expected to improve slightly in the next six months, compared to the same timeframe as last year, with 17% of U.S. adults planning at least one business trip between May and October — typically a slow period for such travel. An encouraging sign that general business activity in the U.S. is on the mend is that business travelers took an average of 6.3 trips in the past 12 months, which is the highest average number in the past five years.

Roger Dow, president and CEO of the U.S. Travel Association, said, "We are seeing a renewed enthusiasm for travel among consumers and barring any dramatic events, we believe that domestic travel will remain on solid footing through the summer travel season."

According to an Orbitz survey of nearly 1,000 consumers, 53% of respondents plan to spend more than $1,500 for summer travel compared to 39% in 2011. Orbitz’s survey showed that 77% of consumers are taking a vacation this summer — slightly more than the U.S. Travel Association projects — with more than half (56%) planning to travel by car and 39% by air. As well, the majority of consumers (60%) in the Orbitz survey said that gas prices will be a factor in where they travel this summer.

Based on the Orbitz survey, more consumers are planning to travel in July (31%) rather than in June (18%) or August (20%) with the rest of travelers still undecided. "Hotel prices in many of the most popular destination this summer are cheaper in June vs. July, including those in eight of the Orbitz top 10 summer destinations," said Jeanenne Tornatore, senior editor of Orbitz.com. "Travelers that can be flexible on travel dates should consider a June getaway when daily hotel rates are 6% less expensive, on average."

Orbitz Top Ten Summer Destinations for 2012 (parenthesis shows how the city ranked in 2011):

1. Las Vegas (2)

2. New York (6)

3. Orlando (1)

4. Los Angeles (4)

5. Seattle (3)

6. San Fransisco (7)

7. Denver (5)

8. Chicago (8)

9. Boston (10)

10. Cancun (9)

Other highlights from the Orbitz Summer Travel Insider Index include:

• Las Vegas tops the list as the most popular destination for summer 2012 with affordable hotel rates ($95 per night) likely being a key factor.

• Of the top 10 summer hotspots, Denver is the only city experiencing a decrease in average daily hotel rates.

• More travelers feel guilty about leaving behind their pet (33%) than their children (30%) when they go on vacation.

• Americans wish the U.S. would follow Europe's suit regarding paid time off, with 44% of survey respondents believing the government should mandate companies to offer at least four weeks of vacation per year.

• Nearly half (47%) of survey respondents are getting summer travel ideas through social media platforms such as Facebook and Pinterest.

• 54% of consumers said they would attend the Summer Olympics in London this year if money were no object.

• The majority of consumers plan to travel domestically (81%), but more consumers are planning to travel internationally this year (19% vs. 11% in 2011).