By Betty Yu

OAKLAND (CBS SF) — Their slogan says “travel is our deal,” but pilots who fly for Allegiant Air say the company is cutting too many corners at the cost of safety.

The airline is an ultra-low fare, high-fee carrier that uses mostly old planes that can be bought or leased on the cheap.

READ MORE: One Killed, One Injured In Berkeley Vehicle-Pedestrian Collision

The pilots’ union wrote a letter to the airline’s board complaining about what it says is Allegiant’s bare minimum approach to safety and maintenance.

The letter points to 38 potentially dangerous incidents in the first three months of this year. They include engine failures, pressurization problems, smoke in the cockpit, and radar issues.

Earlier this month, a pilot made an emergency landing at the Tampa area airport, and passengers evacuated using emergency exit slides after smoke was noticed in the cabin.

READ MORE: KPIX 5 Exclusive: Older Concrete Buildings in San Francisco Raise Earthquake Concerns

In Boise, passengers had to stand on the wing of an allegiant air jet. They evacuated after possibly seeing smoke outside the plane.

In 2013, an Allegiant Air flight out of Oakland took off more than 11 hours behind schedule for a 90 minute trip when a cable controlling the front landing gear snapped, and a second plane also had a mechanical problem.

Allegiant opened a hub in Oakland in 2012.

It now flies to 8 cities, including Bellingham, Washington, Omaha and Phoenix-Mesa. Allegiant also flies from Stockton and Monterey.

MORE NEWS: Update: Former California Senator Barbara Boxer Assaulted, Robbed In Oakland's Jack London District

The airline received mostly one-star yelp reviews for the Oakland hub, warning others of severe delays.  One passenger commented that the airline has “sketchy planes.  I worry that the plane is gonna crash every time.”