A simple answer would be, hopefully very safe and carefully. However, in reality to do so requires a lot of planning and experience.
Manuals and checklists are provided to ensure this process is completed correctly.
Before your flight can depart a flight plan is loaded into the on board navigation system manually or through an automatic up link.
This is an electronic Point A to B map.
Once the flight deck preparation is complete your flight will be ready to depart the gate after the boarding process is complete.
Although your flight is ready to depart it cannot leave the gate until it has permission to do so from a Ramp or Ground Traffic Controller.
There is no key involved. For the most part this is an automatic process initiated and monitored by the pilot.
If a lengthy taxi time is anticipated it is possible the airplane will taxi (move around) with only one engine running. This can save a considerable amount of fuel and money. At idle, a jet engine can use more than 100 gallons per hour. With a fleet of 600 airplanes, using just 10 gallons less fuel per hour per airplane with Jet Fuel at $2.00 per gallon equals about a $12,000 savings in fuel cost.
In order for the airplane to fly it must produce lift. In essence it must overcome the effect of gravity.
The aircraft wing is the primary source for producing lift and flaps supplement it's lift producing capability.
Flaps are used for takeoffs and landings with the amount used depending on the airplane weight and configuration.
At the gate or as the airplane is taxiing to the runway the airplane’s weight is calculated. This is important because it determines what configuration will be used to allow for a safe takeoff.
With the aircraft weight determined safe takeoff speeds and power settings can be determined.
Sometimes this calculation is delayed and you cannot takeoff until it is complete. Although unusual you might find yourself in a “We are waiting for takeoff numbers” delay which is normally brief.
For maintenance and fuel savings along with other safety considerations your flight may not always takeoff at full power. An airplane with few passengers departing on a long runway might be such case.
Have you ever stuck your hand out the window of a moving car while your mom was not looking? What happens? Your hand wants to fly especially if your mom has a lead foot. However, if she drives slow like me nothing much happens.
On a hot day with all things equal the airplane must go faster to fly than on a cold day. Most commercial airplanes safely become airborne between 150-200 miles per hour although airplane speeds are referenced in knots.
“Northwest 807, turn right heading 230, cleared for takeoff”
When conditions allow most airplanes will take off with a headwind to reduce the amount of runway required to become airborne. That is why at different times you may depart an airport in a different direction depending on surface winds.
Using throttle levers located on a center console, pilots set a pre-determined power setting.
As the airplane gains speed pilots are required to make system checks to ensure the airplane can be safely taken airborne. Any malfunctions require a swift decision that is made based on experience, aircraft procedures and airline policies. 99.9 percent of the time reaching the correct calculated lift off speed your flight will become safely airborne.
A coordination of flight control surfaces on the tail along with the wings and you are accelerating to your cruising altitude. You will be traveling about 500 miles an hour when you get there.
With nice weather it will seem like you are sitting in a comfortable bus except you will soon be about 5 miles above the earth. Enjoy your flight.