Northrop Grumman's Stargazer airplane was flying with Pegasus and LINK in a holding pattern to line up with the drop zone for a drop and launch at 08:35 UTC.
NASA has not set a new date for the Pegasus-XL launch.
NASA scrubbed the Pegasus-XL launch because an issue prevented the rocket from being deployed from Stargazer.
The Pegasus XL launch was postponed.
The Pegasus XL mission will drop and ignite at an altitude of 40,000 feet.
The next Pegasus-XL launch attempt for the Swift Boost Mission is scheduled for tomorrow at 09:43 UTC.
Northrop integrated Link with the Pegasus rocket and the Pegasus with its L-1011 carrier aircraft at Wallops Flight Facility in Virginia.
Link will begin its mission about 13 minutes after launch, when it separates from the Pegasus upper stage.
Northrop Grumman has only one Pegasus mission on contract today.
Katalyst also selected Pegasus XL because it was far cheaper than buying a dedicated Falcon 9 launch.
Katalyst selected Pegasus XL because it could reach Swift’s orbit and offered the reliability and schedule capability needed for the time-sensitive launch.
Wallops supported spacecraft integration and Pegasus integration within weeks for the Swift Boost Mission.
The Pegasus-XL launch of the Swift Boost Mission has been delayed by 3 days to June 30 between 07:30 and 13:28 UTC.
Pegasus is an air-launched rocket that is released from an L-1011 Stargazer aircraft.
The Pegasus mission to Swift will launch from Kwajalein Atoll.
Pegasus can operate without relying on a single launch site.
Pegasus has flown more than 45 launches since 1990.
Northrop Grumman plans a complete avionics upgrade for Pegasus.
The Pegasus launch of Swift Boost Mission is scheduled for NET June 27 between 09:00 and 14:28 UTC.
The Pegasus mission will launch from Kwajalein Atoll in the Marshall Islands.