Charging UK travellers one of the highest aviation taxes in the world "simply doesn't make sense", so air passenger duty (APD) will be scrapped in Scotland, Nicola Sturgeon has pledged.

The SNP leader unveiled her plans to make Scotland "open for business" and confirmed her pledge to halve APD and ultimately abolish it.

APD was introduced by Conservative chancellor Kenneth Clarke in 1993 as a revenue-raising tool and doubled by Labour chancellor Gordon Brown in 2007 to encourage a reduction in air pollution.

Ms Sturgeon said removing it will "dramatically increase Scotland's international connectivity and boost our tourist industry".

The SNP has also pledged to maintain the small business bonus throughout the next Parliament, connect every household to superfast broadband by 2021 and triple the number of exporting advisers in Scotland.

It will fund new innovation and investment hubs in London, Dublin and Brussels to attract inward investment and improve domestic access to new markets and investors, and increase apprenticeships in engineering, design and technology.

Ms Sturgeon was campaigning in Anniesland, Glasgow, with SNP candidate Bill Kidd.

She said: "Under the SNP, Scotland has the most competitive business tax environment in the UK, the number of registered businesses is at an all-time high and we are consistently ranked in the top two regions outside London for foreign direct investment.

"We want to build on these strengths and the SNP will use all of the powers available to us - both existing and new - to help all our businesses thrive.

"Our small business bonus scheme has supported small and medium-sized businesses through some tough economic times and today I am giving them the certainty that we will guarantee this relief for the lifetime of the next Parliament.

"A major priority of the next SNP government will be to improve Scotland's connectivity and increase inward investment.

"Air passenger duty is one of the highest taxes of its kind in the world - which simply doesn't make sense - which is why we'll use the new powers coming to the Scottish Parliament to halve APD, and ultimately abolish it - to dramatically increase Scotland's international connectivity and boost our tourist industry.

"We'll make sure that businesses the length and breadth of Scotland get the connectivity they need by an ambitious programme to roll out superfast broadband to 100% of properties."

Labour insisted its tax plans will make £3 billion more cash available for public services than those proposed by the SNP over the next four years.

The nationalists have already pledged there will be no rise in the basic rate of income tax over the term of the next Scottish Parliament and have ruled out restoring the 50p top rate of tax for the highest earners in 2017-18.

In contrast, Labour wants to return the tax rate for those earning £150,000 a year or more to 50p and has committed to put 1p on the basic rate of the charge.

Jackie Baillie, the party's public services spokesman, said the difference meant the SNP must spell out where cuts would be made.

Ms Baillie, who was campaigning in Bathgate, West Lothian, said: ''The difference between Labour and the SNP is £3 billion.

"That's the amount Labour would raise by using the powers to stop the cuts to public services.

''The SNP refuse to tax the richest to protect the rest. They now have to spell out where the axe would fall.''

She promised a Labour Scottish government would make an anti-austerity pledge - saying this would be a guarantee that spending on day-to-day public services will rise in real terms.

''Faced with a choice between using the powers of the Parliament to invest in the future or carrying on with the SNP's cuts, Labour will use the powers,'' she added.