Hi Freddie - A laptop can be used for all the things you mentioned. Let me preface this by saying I'm somewhat biased here, because I sell laptops. I used to buy Dell products, but I got really frustrated with their customer support which has been outsourced to India. When I need repair work, I had to spend a long time on hold and often call back until I could get someone who was able to veer from their script and address my issue.
I now sell laptops that are put together locally here in Portland, Oregon. They are a multinational corporation, but their headquarters are based here. When I need service I don't have to hold forever to speak to someone and I get excellent service. If you're interested, you can send me a private message and I'll give you more details.
The last thing I'll say is that I would recommend you get a Centrino processor, also called Intel M. The battery will last longer with this processor and the laptop will not get as warm if it's actually in your lap. For a long flight, if you plan to watch movies the entire flight, you'll probably still need an extra battery.
Hope this helps.
Lis