Florida World Disneyland

It's called DisneyWorld in Orlando, Florida. Disneyland refers to the theme park in Anaheim, California.

There're four theme parks in DisneyWorld. Expect to spend at least one day in each theme park. Plus there are two Universal Studio theme parks in Orlando. Spend at least 1 day there.

You can go there by plane, the closest airport is Orlando.

You can survive without a car if you are only interested in the theme parks. It will be the best if you just stay at a Disney hotel. They have plenty of free shuttles, you don't have to worry about parking. Plus, disney resort guests got access to "resort guests" only hours.

I wouldn't recommand you to go to Disneyland for only one day since there would be so many things to do and you are not going to go through a lot in only one day. Spend at least 3 to 4 days there since there are really much to do. If you get bored (most pobably not but just in case), you can really go to universal studio because it would be even more heavenly compare to any other theme park.
I would also recommand you to buy a fast pass in both disneyland and universal studio even it cause a little bit more. you have already pay for the air ticket so i don't see why not buying a fast pass to avoid all the long lines of waiting.