Those early boarders have first crack at the best seats and overhead bin space.

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Passengers get more legroom, complimentary food and beverages, and reserved overhead bin space.

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Under the front hood it will have a small storage space, "like an overhead bin" on an airplane, Tata says.

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Zone one boarding is for everybody who purchases the right to carry on a bag that will go in the overhead bin.

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American tested the idea in seven cities earlier this year and found getting people without overhead bin luggage on early sped up boarding time and improved on-time arrival performance.

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If you typically reserve a seat in the back of the plane to get earlier boarding and more availability of overhead bin space, you might now want to reserve a window seat on United.

WSJ: Summer Air-Travel Survival Guide

Sanitize your hands before eating, drinking and after retrieving something from the overhead bin or returning from the restroom, and you have just cut your chances of getting infected by at least 40 percent.

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An American Airlines jet bound for Chicago had pulled away from the terminal and was preparing to take off from San Diego International Airport Sunday afternoon when a woman pulled a sweater from an overhead bin and what appeared to be a grenade fell from it and rolled down the aisle, to the amazement of passengers.

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American offers Group 2 boarding, right after elite-level frequent fliers, to passengers without overhead-bin luggage.

WSJ: Summer Air-Travel Survival Guide

Additionally, Cush said, early boarding passengers would sometimes glance up at all the empty bin space overhead and then place their carry-on in the bin.

FORBES: Will American's New Boarding Process Work? It Failed At Virgin America.