Ajay carries two obviously empty suitcases in one hand into the hotel in Kathmandu.
The airplane's wing has a wingtip fence, which weren't introduced to the passenger/commercial airplanes until the 1985 with Airbus 310. The specific shape of wing and wingtip fence denotes this airplane as a part of Airbus A320 family. A320 made a maiden flight in 1987 and entered into commercial service in 1988.
When Lena's passport is shown at customs it shows a Dutch address with a postal code. Postal codes were only introduced in 1977 in the Netherlands.
Marie is using Helena's passport while travelling out of Thailand. The passport states that the holder has blue eyes and blonde hair, none of which apply to Marie. Later on, the Nepalese police inspector questions them holding their passports and still doesn't notice the obvious misinformation on the passport.