As you might know The White Eagle is the national coat of arms of Poland. It is a stylized white eagle with a golden beak and talons, and wearing a golden crown, in a red shield.. The White Eagle emblem originated when Poland's legendary founder Lech saw a white eagle's nest. When he looked at the bird, a ray of sunshine from the red setting sun fell on its wings, so they appeared tipped with gold, the rest of the eagle was pure white. He was delighted and decided to settle there and placed the eagle on his emblem. He also named the place Gniezdno , currently Gniezno, from the Polish word gniazdo ("nest").
So... the White and the Red became The Polish National colours. The National Flag of Poland consists of these same colours put on the banner as two horizontal strips. The first top one is the white one and the second is the red one.
The Partitions of Poland or Partitions of the Polish–Lithuanian Commonwealth are three partitions which took place in the second half of the 18th century and ended the existence of the Polish–Lithuanian Commonwealth resulting in the elimination of sovereign Poland for 123 years. The partitions were perpetrated by the Russian Empire, the Kingdom of Prussia and Habsburg Austria, which divided up the Commonwealth lands among themselves progressively in the process of territorial seizures.
After the WW1 in 1918, Poland regained independence and became a sovereign land in the middle of the Europe . The young country had to hold all national structures including the Army. Many Polish pilots , who fought and served in the WW1 Armies of the former invaders returned Poland and started to organise the Polish Air Force with captured invaders' stuff. Most of planes was seized at Lawica airfield near Poznan. These planes were ex-German invader's equipment and needed to be re-painted with national markings. At that time there appeared planes with the Polish colours that had many different forms.. most frequently shields party per bend, pale, or red letter "Z" in a white square or white-red bands. The four-field, red-white checkerboard, was first used as a personal insignia of the Polish fighter pilot Stefan Stec, who was servicing in the Austrian AF. On a such marked plane Stec arrived by air from being besieged Lvov to Warsaw on the 15th Novemeber 1918. The Commander of the Polish AF Colonel Hipolit Łossowski found the kind of marking as the perfect one for the PAF insignia. Officially, it was adapted as the Polish national roundel on 1 December, 1918.
F/O. Stefan Stec's Fokker E.V 175/18 .
In 1921 contrasting red and white border was added, but without specified dimension. In 1930 the ratio of border to fields was fixed at 1:5. According to current regulations, an additional gray border can be added, 1:6 the size of the field, if the insignia is on white or red background.
Between 1960s and 1980s the checkerboard (usually rotated 45 degrees) was also painted on turrets and hulls of Polish Army's tanks and APCs. The tradition was however discontinued.
In 1993 the color order was changed from red-dominant (red in the upper left) to white-dominant, to conform to heraldic rules, though ignoring the 70-year old tradition. The first white-dominant checkerboard was used in 1940 in France.
1918-1921
1921-1993
1993.....
I hope this can help.