I always wondered why the navies didn't always room in battle groups. Carriers of any kind are exspensive if not in monetery terms than in the cost of lives. It takes alot to keep a wing of fighters up. Think of our real life carriers today, 5,000 people to keep those jets and planes in the air. No matter how big you ship is, you still have a finate number of foodstuffs and armaments on board the ship, so why not go in groups and take a supply ship with you, He holds alot of supplies and very few people.
Carriers today are the fastest ships (not boats don't get them confused) in our navy (USA) and I'm not just saying that because my dad builds them for a living. On the USS Guston Hall (assult ship, not the 'baby carrier' like the Kersarge either) they have a picture of when a fast firgate radioed the Capn of the carrier (big E or Nimitz I don't remember now) and he told the capn he'd seem him in the med. The carrier captin didn't like that and the Flag officer agreed, and they all went flank speed to gabrator. Any way the carrier is about half a mile ahead of every one else and they all have big ole wakes behind them.
Maybe that was the USS Monterey (spelling), which is a curiser that I had the pleasure of riding on from the weapons station down to Norfolk (I was in ROTC). They had an unclassfied top speed of 31 knots, the USS Truman has an unclassifed top speed of 33 knots and can get there faster than the crusier. Basically what I'm getting at is shear size can give you a more impressive power plant for faster speeds.