Skyscanner. My favorite of the bunch. This app pulls from all the travel sites so you have all the information you need for flight, hotel and car rental in one spot without web surfing. My favorite features are the "everywhere" feature and use of the calendar. The calendar option for flight search is perfect if you have a flexible schedule - enter departure and arrival cities. For dates - select the whole month and it will give the cheapest dates to travel in the selected month. The everywhere feature trumps that though. For instance, I want to plan a trip from Dallas (and open to destination), I simply enter "everywhere" as my destination and skyscanner will give a list of potential destinations (domestic and international) from cheapest to most expensive. Perfect for spontenous and flexible travellers.
Splitwise. On my recent trip on Spain, after spending hours trying to reconcile expense etc (downsize of accountants traveling together), the first thing I did when I returned was download Spiltwise from my cloud. This is the perfect app for group travel. It keeps track of who is paying for what and how much needs to be refunded. In some countries, you can link up Splitwise to PayPal or Venmo to settle bills immediately.
Venmo. Of all the payment apps out there, this is my favorite one. I have access to it anywhere in the world and I can settle my portion of group travel expenses on the spot without the hassle of tranferring funds and waiting days etc.
Hotel Tonight. I recommend this to every and anyone. This apps with last minute hotel reservation (for a fraction of the cost). Using this app, last fall I booked a hotel in Paris, right off Champ Elysees with a view of Eiffel tower and less than a block from the Arc De Triomphe for less than a hundred dollars per night. Need I say more. The only downsize with this app, you can only see rates/availability seven days out. That is not so great if you have an OCD planning side like me.
Pack Point. I don't use this much these days because I am too lazy to type up the activites etc, but it has been very helpful in the past and friends I have recommended this app to swear by it. This app helps with packing tips based on destination, weather at your destination, and activities planned.
Your turn, what apps do you use for travel planning ?