There are a number of reasons for which you might want to know the flight status. The status is primarily about real-time information on flights and aircraft and tells us about the arrivals, departures, delays and the condition of aircraft. The agencies which provide the information on flight status have to take references and data from a number of sources in order to put in place an accurate status-describing system.
One source of information is the government regulator which collects the data feed of Aircraft Situation Display to Industry. This data contains the filings of the pilots which are done before the take-off of the plane. These filings include time of departure and arrival and the route to be taken. Information is also taken from the Global Distribution System (GDS) and direct feeds from the airports.
Some of the best flight status service providers have global coverage. These also provide the services of mapping the code-share cheap flights. For the delayed flights, it maps the information displayed on the airport board to the affected flight. For using the services of these providers for checking status of flights, you need to make the searches either with the airport or the flight information.
It shall be noted that there will be some difference in the flight status information from different sources since the accumulation and analysis of data from various sources could be discrepant which will ultimately affect cheap flights information to be provided to the people.