Identify your market.
Determine who you want to offer your airline charter service to. Who do you think will make good customers and how big a market is this? Can you realistically do business offering your services to this market? What are their needs, the type of services they prefer or wished other airlines offered and is there a potential for expansion with this market alone? If there is none, find out if it's possible to expand to other market sectors.
This early, you might also want to decide whether you only want to cater to individual or corporate clients or if you would like to include freight or cargo as part of your business. Either way can be lucrative and if you want to combine both, you should be able to provide sufficient equipment and manpower. As a startup, this is one aspect worth looking into.
Know who your competitors are.
The airline charter business is highly competitive and the sluggish economy means you'll have to work doubly hard. To find out what types of services are currently being offered, look for companies that are involved in the field.
Learn as much as you can about them – how long they've been in business, what types of services they offer, how many people they employ, what their market share is, what makes them successful, etc. This will help you determine what types of needs are still not being met by these carriers and what steps you need to take so you can compete with them directly.
Another great way to get into the airline charter business is to buy into a franchise. As a startup, your baby steps will be guided and you'll have a system you can follow. With a franchise, you have the advantage of a known brand and won't have to learn the industry on your own.