If you are 1 degree off heading how far would you be off 1000 miles away?

If you are 1 degree off heading over a distance of 1000 miles, you would be off by approximately 17.45 miles. This calculation is based on the formula for calculating the distance off course due to a heading error, which involves trigonometry and the Earth's radius. Therefore, even a small error in heading can result in a significant deviation over a long distance.