The per-hour limits apply to links created through the Bitly API. By default, the hourly limit is set to 10,000 links/hour for an Enterprise account and 1,000 links/hour for other subscription plans. Note that there are also monthly limits for API calls.
The per-minute limit is 1/10th of the hourly limit, and it resets every minute. For example, an hourly limit of 10k calls translates to a per-minute limit of 1,000 calls.
To increase your limits, contact our sales team. If you have an Enterprise subscription, contact your account manager.