SINGAPORE - The first commercial flight landed and later took off from Changi Airport's new Terminal 4 on Friday night, amid much buzz.

In all, 180 passengers on board AirAsia flight AK9723 from Kuala Lumpur landed at T4 at about 9.10pm. The return flight AK9722 carried 166 passengers and departed at about 9.50pm.

Departing passengers were treated to complimentary arcade machines and neck masssages since the terminal is not open yet so there were no shops and eateries operating.

Passengers were told to gather at T1, where AirAsia now operates from, before being bussed to T4 - about three minutes away.

On the bus, which The Straits Times was on, they were briefed by airport staff on what to expect at the new terminal, which opens officially later this year.

Unlike the three other terminals, T4 offers a start-to-end automated system to reduce reliance on manpower, though it also features manual counters.

For the first time at Changi, the new terminal also features a facial recognition system which will capture the passenger's photo at different stations.

From check-in to bag tagging, as well as bag drop, immigration clearance and boarding, it was all automated.

The systems and processes, which The Straits Times also tested, all worked fine.

Changi Airport Group spokesman Ivan Tan said many passengers used the self-service options, and assistance was provided to those who were not familiar with the system.

"All the airport systems were tested in a real operating environment and functioned as expected," he said.

Most of the passengers said they were excited about the new facilities.

Upon arriving at the new terminal, many were impressed with the modern facade, and started whipping out their handphones to take selfies, and even to film the self-baggage check-in process.

But some expressed concerns about security and accessibility.

Doctor Benny Ang, 60, said that he had some concerns about security, when it came to the self-check-in baggage machines.

"There might be some concern with bag tampering, when there is no staff around to physically help us to check in our bags," said Mr Ang, who is travelling with four other family members for the long weekend.

"When it's all done by the machine, some people might wonder where the bags will be going to."

However, he added that the self-service machines were easy to use as they are similar to those used in other airports.

"They were easy to use and the instructions were clear, and many staff were on hand to help, although today the crowd is quite small."

AirAsia had sent SMS messages and emails informing passengers in advance that they would be departing from T4 on a test flight. Calls were also made to passengers though some could not be contacted.

Of the five travellers The Straits Times spoke to, none of them realised that they were going to be taking the first commercial flight at a new terminal at the point of booking their tickets.

"If I had known, I would not have chosen this flight," said a traveller who wanted to be known as Ms Yong and is in her 50s.

She is a frequent traveller with AirAsia, taking the airline's flights at least three times every month over the past three years.

"The airline informed us (through email) that we had to arrive three hours early for this flight. I was worried that if I came later, there would not be access to the new terminal," added the human resource manager.

Others were more than happy to be selected for the first test flight at the new terminal.

Mr Soh Chin Yong, 31, banker, said that he was "excited" and "privileged".

"I didn't know that it was going to be there!" he said.