BMI Regional is launching as a fully independent airline, five months after being bought by a consortium.
The business was carved out of BMI in May, after the larger airline was taken over by British Airways' owner, IAG.
BMI Regional, which operates 18 Embraer jets on scheduled services as well as leasing and charter contracts in the UK and Europe, was bought for £8m by Sector Aviation Holdings (SAH).
The airline is launching its own website and a new airline code - BM.
BMI Regional will run a total of four domestic and 11 European routes, having recently announced two new twice-daily services from Aberdeen to Bristol and Manchester to Antwerp in Belgium.
The airline's head office is at East Midlands Airport but its operations base is in Aberdeen.
SAH chairman Ian Woodley told BBC Scotland that it had taken five months of hard work to reach this point.
"This marks another step forward for our business," he said.
"It is the end of what has been roughly 20 weeks of intensive work, where we have been basically recreating the regional airline as a completely standalone operation from what was - if you like to call it - its original mothership, which was BMI.
"In some respects it would probably be easier to start an airline from scratch.
"You have this mothership with so many umbilical cords, all attached to a subsidiary."
Mr Woodley, who founded BMI Regional's predecessor Business Air in 1987 before selling it to BMI in 1996, said the process had involved severing all connections and then negotiating new contracts.
He added: "We have also had to introduce our own entire global distribution reservation system, which some people in the industry liken to open-heart surgery.
"But we've had to do all this at the same time as still flying our existing passengers and still maintaining our on-time departure performance."
Mr Woodley said the company planned to keep the title BMI Regional - at least for the time being.
Under the terms of its agreement with IAG, SAH will have full rights to the BMI name from April next year.
He said: "At the moment we will continue with BMI Regional.
"There is a bit of a decision to take in-house, and we are also going to canvass some of our customers about whether we keep the 'Regional' or whether we just drop the 'Regional' and come back to BMI mainline.
"It is a decision that we will take probably this side of Christmas."
Mr Woodley said his airline was "in some negotiations" over wet leasing arrangements - providing an aircraft, complete crew, maintenance and insurance (ACMI) to other European airlines.
He described the company's business as "quite a mix" of different operations.
He added: "It's a mix that we like because we don't want to be dependent upon just one type of revenue stream.
"Once we are fit for purpose in terms of the full new brand, then we will look to develop new services - but most likely we will delay a decision on some of those until the first of February."