The move will plug almost all the gaps created by long-troubled Flybe going into administration early today.
Loganair has announced it will fly from:
Aberdeen to Belfast City, Birmingham, Manchester and Jersey
Edinburgh to Cardiff, Exeter, Manchester, Newquay and Southampton.
Glasgow to Exeter and Southampton.
Inverness to Belfast City, Birmingham and Jersey.
The routes will be launched between 16 March and 6 July, and operate between once a week and daily.
The airline is creating new 100 posts to operate the new services and is seeking to recruit Flybe staff who lost their jobs when it went into administration.
These include Aberdeen to Cardiff, Humberside, Newcastle, Teesside and Wick.
It will also launch an Aberdeen-Birmingham service, which Loganair is to also operate.
The only other Flybe routes not served by other airlines from Scotland are Edinburgh to Knock in western Ireland, and Bergerac in France, although EasyJet flies to nearby Bordeaux.
Flybe operated to Belfast City from Edinburgh and Glasgow, but EasyJet links the cities to Belfast International.
Flybe also flew between the Scottish cities and Birmingham, but EasyJet has already announced it will operate the routes from the end of the month.
The end of Flybe flights from Edinburgh and Aberdeen to Heathrow and Edinburgh to London City will leave British Airways with a monopoly on the routes - as it already has from Glasgow.
'Comprehensive plan to keep customers flying'
Loganair chief executive Jonathan Hinkles said: “The collapse of a long-standing airline like Flybe marks a desperately sad day, especially for the airline’s dedicated team of employees and for customers facing disruption to their journeys.
"By stepping in quickly with a comprehensive plan, Loganair is aiming to maintain essential air connectivity within the UK regions to keep customers flying, and to offer new employment to former Flybe staff members who are facing an uncertain future today.
“The plan represents the outcome of several weeks of behind-the-scenes contingency planning work, during which we’ve evaluated many routes and aircraft.
"It’s critical to the continued success of our own airline that we refrain from over-expansion, and that our growth can be delivered within our operational and financial means.
"I am confident the plans being announced today are robust and sustainable, enabling former Flybe customers to benefit from Loganair’s high standards of customer service and on-time performance on a range of new routes, with a strong emphasis on those to and from our Scottish heartlands.”
Free train travel
Avanti and TransPennine have extended their offer until next Wednesday, while CrossCountry's continues until Sunday.
Caledonian Sleeper is offering free seats over the next week.
National Express has pledged free coach travel.
P&O Ferries and Ryanair have announced discounted fares for affected travellers.
Loganair previous flew Scottish routes to Manchester, and became a rival to Flybe after their partnership over Highlands and Islands routes broke up in acrimony three years ago.
Flybe, which employed some 300 people in Scotland among 2,400 overall, went into administration with all flights cancelled.
Edinburgh and Glasgow airports advised Flybe passengers not to go to the terminal and visit the Civil Aviation Authority’s website for further advice at www.caa.co.uk/news.
The Scottish Passenger Agents Association (SPAA), which represents travel agents, renewed its call for a £1 levy on air tickets so passengers did not lose money from airline collapses.
President Joanne Dooey said: “An airline failure levy is something the SPAA has long campaigned for.
"Had our suggestion that fares from all UK departures ring fence a simple £1 per ticket passenger levy been listened to when it was first raised 20 years ago, every single passenger who has ever lost money due to an airline failure could have been repatriated or refunded at no cost to the public purse."
Virgin Atlantic, part of a consortium which owns Flybe, said: “We are deeply disappointed Flybe has been unable to secure a viable basis for its continuing operations and has therefore entered administration.
It said it had spent £135 million over the last year with partners Stobart Group and Cyrus Capital Partners in an unsuccessful attempt to keep the airline flying.
It blamed the virus for its decision to pull the plug.
The Virgin spokesperson said: “Sadly, despite the efforts of all involved to turn the airline around, not least the people of Flybe, the impact of COVID-19 on Flybe’s trading means that the consortium can no longer commit to continued financial support."