Many travel businesses continue to be "excluded" from government support despite not trading for almost a year, according to an industry trade body.
The Association of British Travel Agents says tour operators, online travel companies and home-based workers are not eligible for government grants.
It wants sector-specific funding while uncertainty over testing regimes and quarantine continues to hit bookings.
Aviation firms and unions have also issued fresh calls for state aid.
ABTA is calling on the government to make support available for all travel businesses that have been forced to shut due to the pandemic.
"The chancellor said there are extra grants for struggling businesses, yet many travel companies remain excluded from this critical support, despite not being able to generate income over the last 12 months," the association said.
"By focusing grants on retail outlets, businesses including tour operators, online travel companies and home-based workers remain shut out of this much-needed support.
"It is also worth remembering that with overseas travel still closed, in the short to medium term, the income retail travel agents can generate will still be limited."
A number of travel firms have fallen into administration in the last year.
STA Travel, which specialised in long-haul trips for young people, stopped trading last year. In August, the UK's biggest travel agency chain, Hays Travel, cut almost 900 jobs.
In the last week's Budget, the government extended the furlough scheme, business rates relief and VAT reductions. It also extended grants for struggling retail businesses.
"We urge the government to... make grants available to all travel businesses, not just those with retail premises, recognising that the reopening of overseas travel will come later than the other sectors and will likely be gradual," ABTA said.
Travel firms are hoping international travel will be able to resume from 17 May.
The Association of Independent Tour Operators said the government's roadmap "gave a real boost to bookings", but added that many questions remain over hotel quarantine and testing which were dampening demand.
Aviation unions, along with Heathrow and ground handler Swissport, issued fresh calls on Monday for government funding.
They want a Covid testing framework to be rolled out to enable quarantine requirements to be lifted for overseas arrivals into the UK.
Thousands of jobs in the sector have already been lost and around 124,000 continue to be at risk, they say.