Ask the pilot

What is the difference between a pilot, a copilot, and a captain?

All modern aircraft are flown by a two-person crew consisting of a captain and a first officer. The first officer is often referred to in a kind of shorthand slang as the "copilot." The captain normally wears four uniform stripes, and the first officer three. Both are fully qualified to fly the plane in all regimes of flight and usually do so in alternating turns. If a crew is going from New York to Chicago to Seattle, the captain will fly the first leg and the first officer will fly the second. The pilot not flying is still plenty busy, trust me, working the communications radios, programming navigational computers, and so forth. Regardless of who is driving, the captain has ultimate authority and command over the flight and a larger paycheck to go with it. First officers upgrade to captain as their seniority allows.

A few older-model aircraft still in service, such as the Boeing 727, require a third pilot called the second officer or "flight engineer." Uniform-wise, this pilot is indistinguishable from a first officer as he or she typically wears the same three-stripe epaulets. On many long-haul flights, one or more relief crewmembers may also be aboard to temporarily take the place of a captain or first officer during designated rest periods.

Sometimes when landing, I see a long thin trail of mist coming from the wingtip. What is this? My friend says it's fuel being dumped to lighten the plane.

Maybe that friend is the same person who told another reader that the contents of airplane toilets are jettisoned into the sky after flushing. What you're seeing is moisture, condensed into a stream as the airflow whips around the wingtip. Wingtips spin off an invisible vortex of air -- something like a miniature sideways tornado -- and this moisture stream is, in part, a visible manifestation.

Why am I asked to store my tray table for takeoff and landing?

So that in the event of an impact or sudden deceleration you don't impale yourself on it. Additionally, keeping the trays up allows for a clear path to the aisle during an emergency evacuation. The restriction on seat recline is for similar reasons. First, it restricts head and body movement, (the high seat backs lessen the severity of whiplash-style injuries), while also allowing for a fast dash into the aisle.

As a businessman who travels frequently, I've considered getting a pilot's license and buying or renting small airplanes to commute around the Midwest. How safe and practical is this idea?

Private flying, commonly referred to as general aviation, or "G.A.," flying, is, as you'd expect, entirely different from airline flying. As a flight instructor who routinely evaluated private pilots, my general rule for friends and family members was this: Do not, ever, step into a small plane with somebody I have not met or spoken to first. By typing that sentence I've invited more hate mail from G.A. pilots than Salon's computers are equipped to handle, but so be it. No matter how bright or competent somebody might seem, it is often impossible to gauge how his or her skills as a lawyer, software engineer, or, um, celebrity magazine publisher, might manifest themselves behind the yoke of a small plane. The old Beechcraft Bonanza, a popular G.A. plane for decades, was nicknamed the "doctor killer."

Operating your own single engine plane would not necessarily be more dangerous than driving, but it would depend how often, how far, and in what kind of weather you'd be flying. To commute safely, you'd need to allow yourself considerable flexibility. A basic private-pilot's license will allow you to fly a single-engine plane only in the best meteorological conditions. An instrument rating, good for gray skies and lower visibility, will nonetheless keep you grounded in icing conditions, for instance, or when the weather is very poor.

You would be operating under a completely different set of rules -- both the FAA kind and those of common sense -- from the airlines. Many private pilots are killed when, like JFK Jr., they put themselves in situations above the level of their abilities and/or the capabilities of their airplanes.

Which is the oldest airline?

Tracing the genealogies of various carriers can be complicated, as many companies have changed names and identities. But most airline historians (there really are such things) agree that the world's oldest continuously operating airline is Amsterdam-based KLM (that's Koninklijke Luchtvaart Maatschappij for those of you speaking Dutch), which lists its founding date as 1919. Other pioneers include Colombia's Avianca, also harking back to 1919, and even the national airline of Bolivia, LAB, which started flying in 1925.

In the United States, Northwest is the oldest, having begun operations in 1926. (Northwest's pilot uniforms pay tribute to the airline's origins as a mail carrier by featuring the words "U.S. Mail" in the center of their emblems.) As many people know, KLM and Northwest joined several years ago in the first of the big strategic alliances, but for whatever reason they never exploited their status as two of the world's first airlines.

Do you have questions for Salon's aviation expert? Send them to AskThePilot and look for answers in a future column.

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