The Boeing 737-700ER (Extended Range) is a variant of the popular 737-700 aircraft, designed and manufactured by Boeing Commercial Airplanes. The 737-700ER was first introduced in 2004, as a part of the Next-Generation 737 family. The aircraft was designed to meet the needs of airlines looking for a longer-range, more efficient solution than the existing 737-700.

The 737-700ER is powered by two CFM International CFM56-7B engines, and can carry up to 149 passengers in a two-class configuration. The aircraft features a number of improvements over the standard 737-700, including a modified wing structure that allows for an additional 3,000 pounds of fuel capacity, and winglets which provide additional aerodynamic efficiency. The aircraft also features an increased range of up to 4,400 nautical miles, allowing for longer-range flights.

Boeing designed the 737-700ER to be an efficient alternative to larger, more expensive aircraft. The increased range of the aircraft allows airlines to fly longer routes without the need for refueling, which can be both costly and time consuming. The aircraft has also proven to be popular with low cost carriers, who are able to make use of its efficiency and low operating costs.

Despite its popularity, the 737-700ER has faced some issues with safety over time. In 2007, the European Aviation Safety Agency issued a warning regarding a potential issue with the aircraft's control systems, and in 2009, the Federal Aviation Administration issued a safety directive related to the aircraft's fuel systems. These issues have since been addressed, and the aircraft is now considered to be one of the safest aircraft in the world.

The 737-700ER brings with it a number of innovations and new technologies, such as an advanced avionics suite, fly-by-wire controls, and improved aerodynamic efficiency. The aircraft is also more fuel-efficient than its predecessors, allowing for greater cost savings for airlines.

The 737-700ER is now one of the most common aircraft in operation, with over 800 aircraft in service worldwide. The aircraft has proven to be a popular choice for airlines looking for an efficient and reliable solution for their long-range operations. The aircraft is also a popular choice for low cost carriers, who are able to make use of its low operating costs and efficient performance.

Overall, the Boeing 737-700ER is an extremely popular aircraft, and is considered to be one of the safest and most efficient aircraft in the world. The aircraft brings with it a number of innovations and new technologies, and is an ideal choice for airlines looking for a cost-effective long-range solution.