Senate Democrats are taking aim at United Airlines, following a widely publicized incident that involved a seated passenger being forcibly dragged off a flight in order to accommodate stand-by employees.

In a letter to United Airlines CEO Oscar Munoz, the senators asked him to provide a more detailed account of the incident and United’s policy on boarding then removing ticketed passengers to accommodate United Airlines personnel.

The letter was also signed by U.S. Sens. Sherrod Brown (D-Ohio) Brian Schatz (D-Hawaii), Maggie Hassan (D-N.H.), Dick Durbin (D-Ill.), Chuck Schumer (D-N.Y.), Ed Markey (D-Mass.) Chris Van Hollen (D-Md.) Ron Wyden (D-Ore.), Richard Blumenthal (D-Conn.), Tammy Baldwin (D-WI), Bob Casey (D-Pa.), Amy Klobuchar (D-Minn.), Al Franken (D-Minn), Catherine Cortez Masto (D-Nev.), Cory Booker (D-N.J.), Mazie K. Hirono (D-Hawaii), Tammy Duckworth (D-Ill.), Tom Udall (D-N.M.), Mark Warner (D-Va.), Bob Menendez (D-N.J.), and Jack Reed (D-R.I>).

“While it is common practice for commercial airlines to sell more tickets than there are physical seats on an aircraft to account for potential ‘no-show’ passengers, overselling tickets can have severe consequences for the travelling public,” the letter says.

A variety of questions area addressed to the CEO in the letter. Among them:

What is United Airlines’ standard operating procedure when deciding to forcibly remove passengers, including those resulting from involuntary denied boarding?

How many times in the last year has United Airlines removed a passenger that has already boarded a plane due to overbooking or other reasons outside the customer’s control? How many of these passengers were forcibly removed?

When a passenger is involuntarily denied boarding or asked to deplane due to overbooking, at what stage of the trip does United Airlines provide the passenger with a written statement describing his or her rights and explain why the passenger was involuntarily denied boarding or removed from the aircraft? Was the passenger on Flight 3411 provided these requirements prior to his forcible removal from the aircraft?

A federal cap exists on the amount of money a commercial airline may compensate a passenger for being involuntarily denied boarding or rescheduled for a flight. Why was the full amount of $1,350 not offered to passengers aboard Flight 3411 before the passengers were involuntarily denied boarding and forcibly removed? Does the $1,350 cap serve any benefit to consumers?

Was the Louisville-bound flight oversold prior to including the four United Airlines personnel reported to have been granted seats to enable them to reposition from Chicago to Louisville? If so, were there alternative flight or ground transportation options for these four crew members that could have ensured they arrived in Louisville with sufficient time to board their next flight?  Did United Airlines have the ability to assign other crew members to that flight departing from Louisville? 

Does United Airlines limit the number of airline tickets that may be oversold on each flight?

When purchasing tickets, does United Airlines provide a passenger with information that the flight has been oversold, so that ticket consumer can plan accordingly for the possibility that they may be involuntarily denied boarding for their purchased flight?

Has United Airlines implemented any policy changes as a result of this incident?

Is it the policy of United Airlines to use taxpayer-funded law enforcement to forcibly remove paying passengers for non-security reasons?

In a dispute such as the one that occurred on Flight 3411, what recourse or appeal process do passengers have to dispute an action taken against them by United Airlines during their travel?

The senators asked Munoz to provide responses no later than April 24.