One of the most important things regarding travel (esp. air) is the carry on. It holds all of the necessities but that doesn't mean you have to sacrifice fashion for function. However make sure that the bag is roomy enough that it fits everything and a good closure so that your stuff doesn't spill all over the airplane. Here are a couple of my picks.
This Signature Scarf Print Tote from Coach is super cute and fun to look at, though it might not be quite big enough if your like me and like to pack a change of clothing.
If you are prone to over packing this Signature Strip Large Tote from Coach might just be the answer. It's massive and has a ton of little compartments to keep everything organized.
If you can up your price range this Leather Bays water Bag from Mulberry might be a good option. I haven't seen one of these in person but from the description it seems like it's between the other two in size.
Now remember you can take two carry on bags (pack your purse into a larger bag) so if you get two medium sized bags it's not the end of the world. Just make sure you can carry it before leaving the house!