What procedures are used for midair refueling without air supremacy?
It's actually a problem the US Navy at least has been considering - with improvements in anti-ship missile capability (such as China's Dong-Feng 21D) meaning that carriers are at risk at ranges approaching 900NMi having to keep the ships out of range is taking a large chunk out of the effective range of aircraft such as the F35C which has a range of 1,200NMi and refuelling a "stealth" aircraft with a conventional tanker plane sort of defeats the point.

As a House Armed Services Committee report noted:


  The committee notes that the aircraft carrier air wing has been optimized for striking power and sortie generation and believes that it may not be configured to support the long-range strike required by current and future threat systems. While the introduction of the F-35C will significantly expand stealth capabilities, the F-35C could require increased range to address necessary targets. The committee believes that several options could be used to address this issue to include developing a stealth tanker capability, improved engine technology, or to develop and procure a strike capability that is purposely built to strike at increased range.


The current proposed answer to this is the MQ-25 development of which was approved by the US Navy earlier this year for service in 2024.

The MQ-25 is intended as an un-manned tanker with stealth capabilities delivering fuel for 4-6 aircraft at a range of ~500NMi, as a) a stealth aircraft itself it will be harder to detect and intercept and b) as UCAV if it does get shot down there's no need to think about ejection seats or any other mechanism to protect the crew.