I've carried a number of divers including commercial divers, always returning at low level (500' or 1,000' depending on the dives). One group of commercial divers were extremely reluctant to fly back until they confirmed that the Australian Standards for Occupation Diving (AS2299) permitted it.
The following information is based on the AS 2299:
Recommended Delay Before Exposure To Altitude After Diving
Altitude (m) . Minimum delay before travel to altitude (hrs)
. . . . . . . . .. . . . Category of Dive (see Legend)
. . . . . . . . . . .Category 1 . . Category 2 . .Category 3
0-150 m . . . . . . . Nil . . . . . . . . Nil . . . . . . . 2 hr
150-600 m . . . . . Nil . . . . . . .. 2 hr . . . . . . 12 hr
600-2400 m . . . 12 hr . . . . . . 24 hr . . . . . 48 hr
>2400 m . . . .. . 24 hr . . . . . . 48 hr . . . . . 72 hr
LEGEND:
Category 1: A single dive to ≤ 50% of the DCIEM no-decompression limit, or two short dives within 18h with a total, combined bottom time of ≤ 50% of the no-decompression limit for the depth of the deeper dive. No decompression dives or repetitive dives to have been performed in the preceding few days.
Category 2: Dives exceeding category 1 but not included in Category 3, e.g. one or more dives to ≤ 50% of the no-decompression limits, or a single decompression dive in a day.
Category 3: Repetitive deep diving over multiple days; multiple decompression dives on one day; extreme exposures; omitted decompression, or other adverse events.
Interestingly, the standard makes no allowance for changing atmospheric pressure - with a QNH as high as 997 a person at sea level is physiologically experiencing altitude affects as if they are at 500 feet (150m) on an ISA day.