(CNN)The loud boom was unmistakable aboard United Flight 328 just after takeoff on Saturday. Something had clearly gone very wrong.

Some of the 241 people on the flight from Denver International Airport to Honolulu opened their windows to see an exposed engine spewing flames and pieces of the plane falling away.

Others closed their windows, grabbed their loved ones and prayed. Thousands of feet below in a Denver suburb, people on the ground ran to shelter to dodge debris suddenly plummeting to the earth.

The pilots issued a mayday call and, after turning back to the airport, landed the Boeing 777-200 plane safely. Remarkably, there were no reports of injuries either in the air or on the ground. Still, interviews with passengers show the incident provided a huge scare for everyone involved.

Here's how those in the air and down below said they reacted during those tense moments.