More Americans say they intend to travel this year and most leading travel indicators are positive, according to MMGY Global’s 2015 Portrait of American Travelers (POAT).

The 25th annual survey of 2,832 U.S. adults, the longest continuous survey of its kind in the U.S., also reveals an uncertain outlook for the future growth of online travel agencies (OTAs), a major comeback for the cruise industry, new insights into the preferences of millennial travelers, and who is helping fuel the growth in the sharing economy for travel, among other findings. Among some of the key shifts revealed in the 2015 POAT study:

Brand.com now trumps the OTAs when consumers make reservations: Despite healthy earnings and reports of growth amid continuing industry consolidation in the online space, the POAT survey suggests new challenges for OTAs. Travelers are increasingly migrating from OTAs when making bookings and going directly to travel supplier websites to both research and book travel.

Only 58 percent of travelers surveyed said they obtained travel information from an OTA during the past year, down significantly from the 84 percent who did so in 2014. On the booking front, the survey found that among travelers who regularly seek information from an OTA when planning a vacation, only 13 percent typically book their reservations on these sites, down from 36 percent just one year ago. Respondents cited the main reasons for booking direct are that they will get the best prices by doing so (64 percent) and that they generally find it more convenient than booking with an OTA (67 percent).

Cruising is on the rise even among unexpected audiences: Despite some incidents at sea over the past two years, this year’s POAT reveals that interest in cruising is actually up. In addition, cruising’s appeal extends across all generational groups. Almost half (48 percent) of all travelers are now interested in taking a cruise vacation during the next two years, up 8 percent from the number who expressed interest in 2014.

Millennials along with mature now show the highest growth of interest in cruising. Fifty-one percent of travelers from both of these generational groups are interested in taking a cruise during the next two years. This is just one example of how millennials, now the largest generational group, are fueling overall growth for the travel industry. Millennials appear to find cruising an affordable and convenient vacation option to explore.

Millennials are reshaping the travel industry in surprising ways: Many believe millennials are apt to seek travel experiences in far off and more exotic locales, yet more and more are opting to enjoy adventures in their own backyard. More than any other age cohort, millennials are increasingly interested in “staycationing,” with over half (55 percent) taking a vacation close to home as an alternative to traveling a greater distance during the past year. This figure is up 14 percent from 2014 and up 23 percent since 2013.

Millennials took staycations an average of 3.1 times during the past year, nearly as often as they took traditional vacations, which they did 3.4 times during the past year. According to the survey, 34 percent of millennials intend to take more staycations during the next 12 months. When asked why, the reasons cited most frequently included a desire to stay in one place and relax (37 percent), to spend more time with friends and family (34 percent), and save money for another vacation (30 percent).

Millennials with families are also fueling growth in demand for travel services:. Millennial families intend to take more vacations over the next year than millennial couples, 43 percent versus 27 percent. Millennial families also intend to spend an average of more than $6,000 on vacations during the next 12 months, 19 percent more than they spent on vacations during the previous year. 

Affluent travelers place more trust in third-party website reviews: Affluent travelers (those with an annual household income of more than $150,000) are increasingly turning to travel review sites for advice and recommendations about travel, with more admitting they trust the opinions published on third-party websites over those expressed by their family and friends:

When searching for inspirational travel ideas, fewer affluent travelers are looking to friends and family. Only 37 percent consider the advice of families and friends to be influential, down 11 percent from last year. Forty-one percent of affluent travelers say they visited a travel review site for information about a travel destination or supplier during the past year, up 7 percent from 2014.

Giving even greater weight to reviews and ratings by fellow consumers, 53 percent of affluent travelers now trust review sites more than institutional or organizational ratings such as those published by AAA and Forbes. The top resource cited for advice on both destinations and travel suppliers was TripAdvisor (87 percent).

The Sharing Economy for travel is not just for millennials: Shared travel services are gaining popularity with all generational groups, not just millennials. While millennials are leading the way when it comes to using non-traditional lodging, booking alternative accommodations on sites like Airbnb and HomeAway, and patronizing ride-sharing services like Uber, they are increasingly joined by GenXers and boomers:

According to the survey, seventy-four percent of boomers and 72 percent of GenXers now use shared services and would be interested in doing so again, just slightly less than the 80 percent of millennials. Travelers using ride-sharing services also are using them for different reasons, depending on their age, with some citing safety and cashless payment options as primary reasons for using services like Uber. Among travelers who have used ride sharing on vacation, 79 percent like not having to pay their driver directly and feel safer since the app identifies the driver and handles payment.

MMGY Global’s Portrait of American Travelers surveyed 2,832 U.S. adults who have taken at least one overnight trip of 75 miles or more from home during the previous 12 months, includes over 2,000 households with an annual income between $50,000 and $124,999; over 650 households with an annual income between $125,000 and $249,999; and over 150 households with an annual income of more than $250,000.  Data was collected in February 2015. To obtain a copy of the entire 2015 POAT report, click on MMGY Global.

More from Travel Pulse:

U.S. News Reveals Best Vacation Destinations for 2015-16

WATCH: Can Airline Bathrooms Really Get Any Smaller?

An Insider's Guide to Getting Around in Cuba

How To Keep The Seat Next To You Empty On A Flight

Tourists Arrested For Crashing Drone Into Cathedral