TripAdvisor adds airline ratings to flight search

Mark your calendar: Entrance fees are being waived at all national parks on 17 days in 2011. The National Parks Service recently announced the lineup for this year's fee-free days. They are: January 15-17 (Martin Luther King, Jr. Birthday weekend) April 16-24 (National Park Week) June 21 (First day of summer) September 24 (Public Lands Day) November 11-13 (Veterans Day weekend) For the past couple of summers, national parks have been free on certain weekends, but based on the park service's calendar for 2011, park goers only get a warm-weather freebie on the first day of summer, June 21. In previous years, free-admission summertime weekends were announced only a few months in advance, so we'll let you know if things change and more fee-free days are added. Right now is a great time to start planning a trip that'll take advantage of free admission during National Parks Week. That takes place in April, which, as Budget Travel has suggested before, is a wonderful time to visit Death Valley, Joshua Tree, and Saguaro national parks, among others. MORE FROM BUDGET TRAVEL: Ask Trip Coach: National Parks National Parks (Minus the Crowds) National Parks: Beat the Crowds in January and February

Some of the the country's largest airports are thinking about hiring private firms to replace the Transportation Security Administration's front-line screeners. Sixteen airports, including San Francisco and Kansas City, have switched since 2002, says The Washington Post. Charlotte, N.C., Minneapolis-St. Paul, and Dulles Airport in Washington, D.C., are all considering converting to private contractors, says MSNBC. With private screeners, the security line moves the same way it does when TSA employees handle the process. Passengers take off their shoes, and they are just as likely to face the same pat-downs or full-body scanners as before. The private security firms themselves are vetted by TSA administrators, and their front-line screeners work under TSA rules. Republican Rep. John Mica of Florida, the new chairman of the House Transportation Committee, recently contacted about 200 airports to ask them to switch, reports NPR. Congressman Mica explained his reasoning in a recent editorial: TSA has grown from 16,500 screeners to an army approaching 67,000 personnel.... Rather than operate a huge screening force and human-resources operation, TSA must refocus and direct its mission to develop and implement the best security protocols and procedures. TSA officials respond that the agency is allowed to fire underperforming workers on the spot, in an exception to ordinary rules for federal employees. So there is no advantage on that score to hiring private contractors. Plus, no one has also shown that the government would save money by outsourcing the TSA's screening work to private contractors. TSA Chief John Pistole told ABC News that undercover tests have shown too many weapons getting through airport security. He said that is partly why, last November, he ordered screenings to be beefed up with enhanced pat-downs and full-body scanning machines that can see beneath a traveler's clothing. Even if airports switch to private screening, these enhanced procedures won't go away. What do you think? Should airports fire TSA screeners and hire private contractors? MORE FROM BUDGET TRAVEL How to speed through security 8 outrageous tales of bizarre behavior at security Security: Can new technology read a flier's mind?

Contributing editor Sean O'Neill will be answering your travel questions today, Tuesday, from 1 p.m. to 3 p.m. ET, in a live chat. Follow Budget Travel's Twitter profile @budgettravel to ask your questions or share your own travel tips. If you can't make the chat, tune in next week—same time, same station. If you're savvy enough about Twitter to know what a hashtag is, you may prefer to follow the conversation via #TravelTuesday. MORE FROM BUDGET TRAVEL Ask Trip Coach: Farmstays Ask Trip Coach: Ocean Cruising Ask Trip Coach: House Swapping

Since the beginning of Internet Time, there has been Lonely Planet's Thorn Tree, a place where frequent travelers trade tips with each other. Facebook came along, of course, and now many people simply post a status update to draw out tips from their connections. (For example: "What should I do in Brussels next week?") But your friends and family members may not be as savvy or passionate about travel as you are. So advice from Facebook connections only takes you so far. Same thing with sites like TripIt and Dopplr and TripLine, which have tools to alert your connections about your travels. Some start-ups are trying to create communities of travelers that can interact with each other in a Facebook-style format. My favorite of these is Gogobot. To take full advantage of this site, you need to be willing to be friendly with strangers. Because it is people you've never met who may have the most up-to-date scoop on the best restaurants in L.A., or the smartest way to get to downtown from the airport during a transit strike in Paris. If you're comfortable with creating a new persona for yourself as a capital-T traveler, GogoBot is for you. During my recent weeks of trying it, I've been amazed at the high-quality of tips that users share with each other. The one downside is that Gogbot's community is still fairly small. A site with a much larger pool of travel hobbyists—half-a-million travelers, in fact—is IgoUgo, a community that's overseen by Travelocity. This past fall, it added social tools, such as an "I've Been Here" feature and a "Get Ideas from Other Travelers" button, which together can help you to find like-minded travelers and learn about their tips as well as share your own advice. UPDATE 1p.m.ET: I also ought to mention Travellerspoint, a travel community with 350,000-plus members, who typically seem to travel more frequently than the average American—and are eager to share their insights. Looking for good guesthouses in Goa, India? That's the level of advice you'll find here. On the opposite end of the marketing scale, heavily-promoted site WAYN has been successful at signing up lots of users, but activity has been stagnant in recent years. WAYN used to have a travel-knowledge focus and stand for "Where Are You Now." Today it seems to be more focused on getting users to date each other. Some sites help travelers meet up in real life, once you've already arrived at your destination. Perhaps the best of these sites is Couch Surfing, a site for finding free and cheap places to stay in people's homes. It has a forum for meetups in cities worldwide. Budget Travel also recently covered five other sites that help you make friends on the road. Especially promising is Tripping.com, a social networking site that connects travelers in more than 100 countries. The site stands out for its wide range of safety mechanisms, such as references, anonymous ratings, video validation, and an emergency hotline for all of its members. How good are these sites? Budget Travel recently sent a writer to Istanbul to test many of these online tools. With a smartphone in each hand, Arianne Cohen tested the limits of online networking in a foreign land. No guidebooks. No language skills. Only social media and mobile apps. (Her story: "The Connected Traveler.") It was fun, but it wasn't easy. One tool Cohen says worked well is InterNations.org. She wrote that it's "a global expat community with 230 local branches. If your own social network falls through, this is the place to track down locals who speak your language." So what say you? What's the best social network for travel? MORE FROM BUDGET TRAVEL Five sites that help you make friends on the road Scavenger hunts by cell phone are all the rage "Istanbul with Only Social Media as a Guide."