#1- Office on Your iOS Device; CloudOn. Cost? $5.00 a month. Why? It does a super job of delivering cloud-based versions of Word, Excel and PowerPoint to your iPad -- provided you have an Internet connection, which you might be lacking on an airplane.
#2. Google Drive. Cost? Free! Why? You can collaborate on a text document in real-time with one or more of your colleagues. The feature, just added to the iOS app, lets you see what others type into the document as you're working on it. It's a fantastic way to eliminate the old back-and-forth of sending document revisions over email -- and then, inevitably, getting confused over which version is truly the most recent.
#3. Time Tracking: Toggl Timer. Cost? Free. Why? Toggl is a Web-based service with a clock timer that makes it easy to track hours by project and client. The timer is available as a Windows, Mac, and Linux software utility as well as an iOS and Android app.
There are plenty of other great apps, but for business owners (especially small business owners who are watching their budgets), these applications seem to be the cheapest, most efficient and work the best!
Have a great rest of your weekend!