Protests will be held on Saturday (8 August) at Birmingham, Belfast, Glasgow, Edinburgh and East Midlands airports, with protesters descending on Stansted, Heathrow and Bristol airports on Monday (10 August).
Unite says the sector is at risk of "devastation" unless the government steps in, with 60,000 redundancies already having been announced by airlines, airports and other aviation-related businesses.
"This is in stark difference to the decisive and job-saving actions taken by other countries, such as Germany, France, Italy, Spain and the Netherlands, in relation to their aviation sectors," said the union.
It is also urging members of the public to send Sunak a digital "wish you were here... to save UK aviation jobs" postcard.
Back in March, during his first cash pledge to mitigate the effects of Covid-19, Sunak said he was working with transport secretary Grant Shapps on a "transport support package" to provide sector-specific support for airlines and airports.
Unite said this support, nearly five months later, was still yet to materialise, placing a quarter of a million aviation roles at risk, and a further million roles indirectly supported by the sector.
“The government has ignored warning after warning in the months since the pandemic began and this crucial industry is now facing being devastated, even as other countries have taken decisive steps to protect their aviation sectors," said Unite assistant general secretary Diana Holland.
"Mr Sunak must follow their example and take urgent action.”
National officer Oliver Richardson added: “UK aviation workers, as well as the communities and businesses that rely on the sector, are desperate for Mr Sunak to keep his word.
"He must provide immediate government support so the industry can weather the temporary impacts of the pandemic and emerge once again as a vital driver of the economy."
Unite has joined forces with TUC and the UK’s aviation unions to call for five key measures to support the sector, which are:
- The extension of, and modifications to, the coronavirus job retention scheme to protect employment in the aviation sector;
- Suspension of air passenger duty;
- Public service obligation routes to ensure regional connectivity;
- Business rate relief for airports (as in Scotland and Northern Ireland);
- Extending the period of repayment of loans to aviation companies beyond the current two year maximum
