The phrase "class award space" refers to the availability of seats or tickets in a certain class (economy, business, or first class) that can be obtained through a reward or loyalty program. Full definition
Start looking for business class award space as soon as you know the routes you want to fly and what days you are free to fly them. (upgradedpoints.com)
Although some carriers don't release a lot of business or first class award space in advance, they usually release at least a few seats. (rewardexpert.com)
Korean miles are awesome for the best First Class award space in the world. (milevalue.com)