Video report by ITV News Correspondent Lucy Watson
Angry airline passengers have condemned a flight into Cardiff from a Greek island that has left nearly 200 people having to self-isolate.
Health officials say there are now 16 cases of Covid-19 linked to those who travelled on last Tuesday's Tui flight from Zante.
Officials also believe that seven of those cases were infectious or potentially infectious whilst on the flight, according to Dr Gwen Lowe, consultant in communicable disease control for Public Health Wales.
Dr Lowe said there have been about 30 cases in Wales in the last week that have come back from Zante, confirmed in people who were on different flights and staying in different locations.
In a statement Tui said all those on board were told they had to wear masks, but passengers have told ITV News they didn't feel protected.
Stephanie Whitfield was on the Tui flight to Cardiff and described how passengers were not wearing masks correctly and just seemed to "disregard the rules".
She told ITV Wales that she "didn't feel safe" on board the flight: "I don't think many of the passengers had been completely educated on the use of face masks.
"There were people with their masks underneath their noses, underneath their chins, people were taking them off to speak to other people, taking them off and wandering down the aisle to speak to other people.
"I didn't feel safe and we took the decision before we got back into Cardiff that we were going to self isolate just because we thought it was the responsible thing to do.
"I was sat in the middle seat and the gentleman next to me had his mask around his chin so for me to kind of highlight it to someone I would have then had to spend the next three and a half hours sat next to someone feeling very uncomfortable, so I didn't feel like I was able to do that."
Before arriving back in Cardiff, she and her husband decided to self isolate, and have been doing so since before the news about the flight emerged.
She said they have mild symptoms and are hoping they just have a cold, but are taking a test on Tuesday.
Ms Whitfield said she found out about the whole flight having to self-isolate from friends and on social media before receiving an email.
She said: "I was actually informed by friends who had seen it on the news and they were asking me if that was my flight...so I heard it through social media and messages before I actually saw the news myself and then I received an email about it yesterday afternoon."
Speaking on the BBC's Today programme, Dr Lowe said that in the "last week we've had about 30 cases in Wales that have come back from Zante.
"Different flights on different days staying in different locations. These are confirmed positive cases and we're expecting that number to rise."
She said officials are in the process of reaching all 193 people on the Tui flight.
Asked about whether airlines should be more proactive about telling people to wear masks, Dr Lowe said wearing face coverings "may help" but pointed out that they are an "informal measure", adding that it is difficult for airlines to police.
"If somebody is determined not to wear a mask, people often don't know how to wear masks properly, they touch them a lot, they wear them below their nose, they take them off to eat.
"And if you've got Covid symptoms, that will spread Covid symptoms quite rapidly through a confined space such as aircraft," she said.
Dr Simon Clarke, a microbiologist from the University of Reading said he was "not surprised, something like this was bound to happen sooner rather than later".
He said the fact that air is circulated inside a plane, combined with lots of people in a small and confined space means that "you're more likely to interact with someone or be in reasonably close confines with somebody who is carrying the virus.
"Because these things are carried on the air or on respiratory droplets, it's easy to pick it up."
He continued "there is always a risk" of catching coronavirus on board a plane, but airlines should do everything they can to "mitigate" them.
Dr Clarke continued that passengers should not "move round the plane unnecessarily" as this can "spread the virus around the cabin".
Spencer Birns, interim CEO of Cardiff Airport, said the airport taking ''every necessary measure following today's report'' to facilitate passenger travel.
TUI said an investigation has been launched as concerns by Mrs Whitfield weren't reported during the flight.
"Our crew are trained to the highest standards and in line with European Union Aviation Safety Agency (EASA) guidelines.
"Passengers are informed prior to travel and via PA announcements on the flight that they have to wear masks throughout and are not allowed to move around the cabin."