(CNN) --Frequent flyers on Scandinavian Airlines (SAS) are taking part in one of the first biometric identification trials that uses both iris and fingerprint scans.
Biometry is the technology that can read a person's unique features, such as fingerprints, face or the iris of the eye.
For domestic flights at Umea Airport, in northern Sweden, the biometric recognition technology is now being used during check-in and embarkation.
The six-month trial using 120 volunteer flyers involves smart cards, which store the biometric images electronically.
Each time the card is swiped the information is crosschecked with the scanned iris and finger. In order to respect privacy issues the airline is not storing any personal data.
"SAS wants to use the technology in a new way -- we want to be able to keep the passenger flow going at the airport, even when security demands and additional checking increases in the future," Pia Forsstrom from SAS told CNN.
Amsterdam's Schiphol airport, Vancouver's International Airport and London's Heathrow have all tested similar technology using only iris scans for pre-registered passengers.
The UK study found that the technology reduced the time spent going through Immigration.
New York City's Kennedy, Washington's Dulles, and Tokyo's Narita airports are also considering similar schemes.
The biometric system automatically verifies the identity of passengers. If required it may also be used by the authorities.
"The passenger will fully own the data. The iris and fingerprint information is only stored on the card that the passengers bring with them to the airport," says Forsstrom.
"The card also stores a "key" to the flight reservation in the form of a credit card number or a SAS frequent flyer card number."
After the trial the airline plans to collect opinions on the two different biometrics techniques and then decide which one works better and also the one passengers prefer.
The "2002 World Biometric Report" by consultant Frost and Sullivan showed that fingerprint readers are more popular.
SAS has already tested the technology out internally on access to secure airport areas.
Some airports are already testing biometric ID to identify their staff and enhance security including London City Airport, Fiumicino airport in Rome and Athens International Airport.
The UK, along with other European countries are planning to produce passports containing biometric information by late 2004.