A Qatari foreign ministry press release said on Tuesday the letter relayed Doha’s concerns about the “serious and flagrant violation of international law”.
The statement said Qatar reserved the right to take the necessary measures to defend its sovereignty in accordance with international provisions.
The violations, which occurred on Sunday, were the latest of several such incidents in recent months.
An Emirati military aircraft overflew Qatar’s territorial waters on January 14 without Doha’s authorisation.
On February 25, another Emirati aircraft approached Qatari borders before receiving warnings and switching course.
Emirati and Bahraini military aircraft had similarly overflown Qatar’s exclusive economic zone on March 10 before being intercepted by a Qatari fighter jet.
On March 15, Qatar’s Permanent Representative to the UN, Alya Ahmed bin Saif Al Thani, addressed a letter to UN Secretary-General Antonio Guterres and the president of the UN Security Council, Karel Van Oosterom, saying a UAE military cargo plane violated Qatari airspace on March 4.
On March 26, the UAE alleged that two Qatari fighter jets approached two of its registered commercial aircraft while flying over Bahraini airspace.
A day later, on March 27, Qatar denied that its air force had intercepted two UAE passenger flights on March 26. Qatar’s Civil Aviation Authority (QCAA) said the Emirati statement was an attempt to cover up the UAE’s multiple breaches of Qatari airspace.
A quartet of countries: Saudi Arabia, Egypt, Bahrain and the UAE imposed an economic blockade on Qatar on June 5, 2017, accusing the latter of supporting terrorism. Qatar has categorically denied the allegations.