Runways have centerlines, roads have side stripes. Many students pilots know this from their first flight lesson, or learn it the first time they start taxiing. A runway is designed for one aircraft at a time. There are no "passing lanes" on a runway. The stripe in the middle doesn't divide traffic landing from opposite directions --- it's a target, a goal. This difference between roads and runways may seem subtle at first, but it's a clue about a major distinctive of aviation: precision.
Generally, side stripes give us enough distance from other cars. We can wander around in our lane a fair bit. Some drivers of average-sized vehicles carelessly drift around in their lanes like a ball thrown by a five-year-old at a bumper bowling alley. When these types of drivers take flight lessons, they use the entire runway as one giant lane.
Pilots of different airplanes with widely varying wingspans, though, need more precision to safely taxi, take off, land without hitting the obstacles along the sides of their path. When precise pilots see they're off centerline, they smoothly make the change back toward their target.
Where in life do I wander from side to side? Where do I need to stop drifting around in my lane, and start correcting back to the centerline?
Proverbs 4:25-27