Demand for flights shot sky-high after news that there will be more options for quarantine-free air travel, forcing the Singapore Airlines (SIA) website to crash.
It also resulted in long waiting times of up to three hours at SIA's Orchard Road service centre.
The spike in demand comes as SIA announced yesterday that it will ramp up designated flights for travellers under the Vaccinated Travel Lane (VTL) scheme.
Meanwhile, SIA's budget arm Scoot will resume thrice-weekly non-stop flights between Singapore and Berlin.
The VTL scheme is set to be extended to eight more countries from Oct 19 - Canada, Denmark, France, Italy, the Netherlands, Spain, Britain and the United States.
It will be extended to South Korea from Nov 15.
The update means that Singapore will have VTLs with 11 countries by Nov 15.
The Republic had earlier started VTLs with Brunei and Germany.
All 11 countries, except Brunei, are already open to travellers from Singapore, or will be open by the time the VTL starts.
This would allow Singapore residents to travel, including for leisure, and return without a stay-home notice requirement.
Travellers have to fly into Singapore on designated flights, as part of various requirements under the scheme.
SIA said it will operate VTL services from Amsterdam, Barcelona, Copenhagen, London, Los Angeles, Milan, New York, Paris and Rome from Oct 19.
SIA's VTL services from Seoul will begin on Nov 16.
It currently operates VTL services from Bandar Seri Begawan in Brunei, and from Frankfurt and Munich in Germany.
When The Sunday Times visited SIA's service centre at Ion Orchard yesterday at about 5.30pm, a few people were seen waiting outside but left after being told by staff that there were already 40 to 50 people inside.
Among people who were there was student Ryon Chan, 17. He had been tasked with reserving four tickets for his family so that they could attend his eldest brother's convocation at the University of California, Berkeley, on Dec 18.
"We 'die die' must go," he said.
SIA said it saw very high demand yesterday for its VTL flights, and that agents may take longer to respond to queries as a a result.
Scoot said that on top of resuming thrice-weekly non-stop flights between Singapore and Berlin on Oct 19, it will increase the frequency of its non-VTL Singapore-Athens-Berlin return flights to four times a week with effect from Oct 17. This means that from Oct 19, Scoot will operate daily flights between Singapore and Berlin.
Foreign carriers Air France and KLM Royal Dutch Airlines have also announced plans to launch VTL flights between Singapore and Europe. Air France will offer twice-weekly designated VTL flights from Paris from Oct 21.
KLM will offer twice-weekly designated VTL flights from Amsterdam from Nov 1.
The expansion of the VTLs to nine countries in the coming weeks is Singapore's most ambitious move to reopen its borders since they were forced shut by the coronavirus pandemic in March last year.
Mr Lim Ching Kiat, managing director of air hub development at Changi Airport Group, said the expansion marks another positive step towards the recovery of travel and connectivity for the Singapore air hub.
"The VTLs will make it easier for people to travel for business, leisure and to visit loved ones," said Mr Lim.
He said that the 11 VTL countries announced so far accounted for more than 6.7 million of Changi Airport's passenger traffic in 2019, before the pandemic struck.
This accounts for about 10 per cent of total passenger traffic.
But given that arrivals from VTL countries will be capped at 3,000 travellers daily, it means that volumes will be a fraction of what they were previously.
Mr Philip Goh, regional vice-president for Asia-Pacific at the International Air Transport Association, welcomed Singapore's moves to further open up as well as to halve testing requirements for VTL travellers, from four Covid-19 swab tests to two.