The activists - who include the former Lancaster University student union president Laura Clayson, 28- cut through the airport's perimeter fence and locked themselves together around a Boeing 767 jet chartered by the Home Office to transport people from UK detention centres for repatriation to Africa.
They were all found guilty of an aviation security offence and sentenced at Chelmsford Crown Court to community orders and suspended jail terms.
All 15 had been summonsed to Colchester Magistrates court on April 15 on a charge of aggravated trespass over the same incident.
But tonight, a spokesman for HM Courts and Tribunal Service (HMCTS) told The Guardian newspaper: “This case was incorrectly listed and letters sent in error. We apologise for any inconvenience this may have caused and the hearing on April 15 will be cancelled.”
Raj Chada, Partner at Hodge Jones & Allen, who represents all of the Stansted 15, had written to the CPS urging it to discontinue the matter.
The Stansted 15 said in a statement: "This latest threat of prosecution is cruel and vindictive.
"After spending well over half a million pounds on prosecuting and convicting us of a piece of draconian terror-related legislation, to spend more money on trying us for yet another offence isn't just wasting money, it's playing cold-hearted games with our lives.
"This malicious prosecution is a window in on the kind of psychological punishment people seeking asylum in this country face from the Home Office every single day.
"Our current immigration system is vicious, that's why we will not stop standing together to challenge it."The Stansted 15 were all convicted of the intentional disruption of services at an aerodrome, contrary to section 1 (2) (b) of the Aviation and Maritime Security Act 1990.
The defendants, aged between 27 and 44, are appealing against their conviction over the 2017 incident.
They are: Helen Brewer, 29; Lyndsay Burtonshaw, 28; Nathan Clack, 30; Melanie Evans, 35; Joseph McGahan, 35; Benjamin Smoke, 27; Jyotsna Ram, 33; Nicholas Sigsworth, 29; Melanie Strickland, 35; Alistair Tamlit, 30; Edward Thacker, 29; Emma Hughes, 38; May McKeith, 33 and 44-year-old Ruth Potts.
Thacker, Strickland and Tamlit were sentenced at Chelmsford Crown Court to nine months in prison suspended for 18 months.
The 12 other defendants were given 12-month community orders.