Traditionally, overland travel had been more affordable
but much more time consuming compared to airline travel. At a time associated with higher gasoline costs, improved airport terminal protection and reduced plane ticket price this assumption has been tossed out of the window!

Every approach to journey provides its benefits and drawbacks, as well as your greatest choice depends on which is actually most significant for you.
Cost
To find out whether overland travel or airline travel is actually more affordable; think about the complete cost of every journey. For instance, a budget web site might promote plane tickets before tax or other surcharges which can dramatically increase the amount you will actually be charged.

Overland prices are often complicated to estimate, due to varying fuel prices and the additional costs of providing your own food.
Comfort and ease
Planes in economy classes are not generally regarded as very comfortable.  Nevertheless, you are able snooze, and to stretch your legs every do often.  Overland travel in a car does not allow you the same luxury, unless you alternate drivers and factor in time to stop for short strolls.
Time
In terms of actual travel time, air travel is significantly quicker than overland travel.  However, when you take into account the amount of time involved in getting to the airport and clearing security, it may actually be quicker to complete shorter journeys by road.
Possible Difficulties
Bad weather can affect your travel arrangements whether you chose air travel or overland travel. The one bonus that air travel has here is that you will often be able to claim compensation if your flight is delayed for a significant period of time.  If you chose overland travel, however you are generally expected to be responsible for your own time-keeping so this is not possible.

The final decision between air and land travel can only be made by you as an individual.  I only hope that this list was useful in helping you to remember which factors to take in to account.  I wish you well on your travels, whichever mode of transport you decide on!