Nepal's air industry has boomed in recent years, carrying goods and people between hard-to-reach areas as well as foreign trekkers and climbers, but it has a poor safety record.
Rescuers unsuccessfully scoured a remote mountainous area in western Nepal by helicopter and on foot all day Sunday, as weather hampered search flights.
Nepal Army official Baburam Shrestha told AFP that ground troops would stop at a local school for the night and be joined by additional forces in the morning.
"We will also resume the search operation from our helicopter tomorrow morning once the weather is clear," he said.
Dev Raj Subedi, a spokesman for Pokhara Airport, told AFP that three helicopters had had to turn back.
"Right now we cannot say where exactly where the aircraft is and in what condition," he said.
"There has not been any reporting or information from locals about a big fire or any other such indications."
There were 19 passengers and three crew members on board the missing plane, which left for the town of Jomson at 9:55 am (0410 GMT), airline spokesman Sudarshan Bartaula told AFP.
The passengers included two Germans and four Indians, with the remainder Nepali.
Relatives of those on board gathered outside Pokhara airport, consoling each other as they wept and waited for news.
The Twin Otter aircraft's last known location was in an area around Ghorepani, a village at 2,874 metres (9,429 feet) above sea level, according to the aviation authority.
Jomsom is a popular trekking destination in the Himalayas about 20 minutes by plane from Pokhara, which lies 200 kilometres (120 miles) west of the capital Kathmandu.
Tara Air is a subsidiary of Yeti Airlines, a privately owned domestic carrier which services many remote destinations across Nepal.
It suffered its last fatal accident in 2016 on the same route when a plane with 23 on board crashed into a mountainside in Myagdi district.
Nepal's aviation industry has long been plagued by poor safety due to insufficient training and maintenance. The European Union has banned all Nepali airlines from its airspace over safety concerns.
The Himalayan country also has some of the world's most remote and tricky runways, flanked by snow-capped peaks with approaches that pose a challenge even for accomplished pilots.
The weather can also change quickly in the mountains, creating treacherous flying conditions.
History of crashes
In March 2018, a US-Bangla Airlines plane crash-landed near Kathmandu's notoriously difficult international airport, skidded into a football field and burst into flames.
Fifty-one people died and 20 miraculously escaped the burning wreckage but sustained serious injuries.
An investigation found that the captain suffered an emotional breakdown during the flight, distracting the freshly qualified co-pilot who was at the controls when it crashed.
That accident was Nepal's deadliest since 1992, when all 167 people aboard a Pakistan International Airlines plane died when it crashed on approach to Kathmandu airport.
Just two months earlier a Thai Airways aircraft had crashed near the same airport, killing 113 people. In 2019 Nepal's tourism minister Rabindra Adhikari was among seven people killed when a helicopter crashed in the country's hilly east.
This month Nepal's second international airport opened at Bhairahawa, aiming to give Buddhist pilgrims from across Asia access to the Buddha's birthplace at nearby Lumbini and easing pressure on Kathmandu airport.