Human bottlenecks abound at airports: security checkpoints, bathrooms, immigration, and on jet bridges and in airplane aisles. (How long does it really take to put a bag in the overhead bin?)

United Airlines is trying to get passengers on board faster, but it will require travelers, especially those with the cheapest tickets, to be very patient.

The airline is testing two-boarding lines, instead of the the five separate lanes it has currently, one for each boarding group. Spokeswoman Maddie King said the change was based on feedback from gate agents and customers.

United will use monitors to show which boarding group is being called. Read: no need to crowd the gate before your group is called. The airline is also getting rid of the upgrade list it shows on monitors since passengers are already told they've been upgraded beforehand.

United is using the two-line system at Chicago O'Hare International Airport, Houston George Bush Intercontinental Airport, Los Angeles International Airport, and it will expand the system at other airports this summer.

United used to use this system but switched to five lanes in 2012. Since then, the airline has introduced restrictive basic economy tickets, which for domestic routes, don't include access to overhead bins. In theory, that means that those travelers don't even need to compete for overhead bin space and if gate agents spot them with a large carry-on bag that wouldn't fit under the seat, they can charge travelers $25 for the gate-handling fee plus the $25 to check the bag.

The change at United aims to make the boarding process easier and the change also makes it faster because there is less crowding near the gate, said King. The airline ranked fourth for on-time arrivals in the 12 months ended in March, behind Hawaiian Airlines, Delta Air Lines and Alaska Airlines, according to the Department of Transportation.

United's reduction in boarding lines would bring it more in line with American Airlines and Delta. Southwest does not assign seats ahead of time but separates passengers into groups based on when they've checked in or their level of airline loyalty.

If this sounds unpleasant, airlines, including United, sell early boarding as a ticket add-on.