Spacetime Classes

The numbers shown are the minimum amount of time required to qualify for one of the classes. If a dragon can spend less than two days in space, they're considered flightless.
 * F-Tier: A month or less
 * E-Tier: 6 months or fewer
 * D-Tier: 2 years or fewer
 * C-Tier: 10 years or fewer
 * B-Tier: 50 years or fewer
 * A-Tier: 200 years or fewer
 * S-Tier: More than 200 years