Haji-Ioannou, who wholly owns easyGroup, launched easyJet in 1995, but now holds only a minority stake in the airline. He stands to profit if the judge rules that easyJet is prevented from entering other areas of the travel industry.
The entrepreneur has launched a digital and outdoor ad campaign to promote easyHolidays.co.uk, a yet-to-launch travel proposition that will go into direct competition with a similar service launched by easyJet in 2007.
His group has also set up holding sites for easyFlights.co.uk and easyAir-tours.com.
Haji-Ioannou has accused easyJet of reneging on its brand-licensing agreement to derive three-quarters of all revenue from core aviation activity. A verdict is expected either later this month or in the autumn.
Speaking exclusively to Marketing, Haji-Ioannou confirmed the launch of the easyHolidays.co.uk proposition, but would not give any details.
He said: 'I always announce my new ventures years in advance. The ads have generated several leads for business partners.'
However, he insisted the new brand would benefit consumers, as the 75-25 licensing rule places a 'limit' on how far easyJet can extend a holiday service.
Haji-Ioannou said: 'The easyGroup brand licences always anticipated and, in fact, encouraged a degree of overlap.'
Editor's comment: Method in Stelios' madness