Question: With Hashem's kindnesses, the State of Israel received F-35 Stealth Fighter jets. Should the blessing of Shehechiyanu be recited, or is it not recited because the fighter plane is a weapon of war? If it should be recited, who recites the blessing?
Answer: War indeed causes distress, but for now we are obligated to wage war. The Rambam calls one of the books in the Mishneh Torah Hilchot Melachim U-Milchamot - Laws of Kings and Wars. The censored edition calls this book "Laws of Kings and Their Wars", as if the Nation of Israel only waged wars in the past but no longer does so. This is not true. There is no free nation without war. To our great distress, we therefore must wage war, but we can take pride in the power of the deterrence of Tzahal. How fortunate are we to have merited these planes!
Regarding which blessing to recite: the blessing of "Shehechiyanu" is recited over an object acquired by one person, while the blessing of "Ha-Tov Ve-Ha-Meitiv" is recited over an object acquired for the benefit of more than one person: Hashem is good to me and does good for others )Shulchan Aruch, Orach Chaim 223:2). In this case, the Stealth Fighter jets are obviously for the benefit of the entire Nation of Israel!
Many years ago, I wrote a long Teshuvah that one should recite such a blessing over the acquisition of a pistol (in this case "Shehechiyanu". See Shut She'eilat Shlomo 3:87). This is true all the more for the F-35 jets!
There were Gedolei Yisrael who disagreed with my Teshuvah on the pistol for various reasons, including that it is a weapon of destruction. These included the former Chief Rabbi of Tzahal, Ha-Rav Brigadier General Avi Ronski, Ha-Rav Dov Lior, Ha-Rav Ovadiah Yosef and Ha-Rav David Cohen, Ra"m in our Yeshiva (brought in the book "Ke-Chitzim Be-Yad Gibor Vol. 1, pp. 131-133). Perhaps the four Rabbis who disagreed with me regarding the blessing over a pistol would agree, however, regarding a fighter plane. In any event, I discussed this issue with the current Chief Rabbi of Tzahal, Ha-Rav Brigadier General Ayal Krim, and he agrees that the blessing of "Ha-Tov Ve-Ha-Meitiv" should be recited over the fighter jets. And as the Torah says: And come to the Chief Rabbi of Tzahal who will be in your days (play on the verse "Come to the judge who will be in your days" - Devarim 17:9), and the Chief Rabbi of Tzahal is the halachic authority of the army.
The blessing should be recited by the head of the Israeli Air Force.
And we can add (somewhat in jest) that if the head of the Air Force wants to be strict, and follow all of the opinions, he can buy a new shirt to be worn by a few people and recite the blessing "Ha-Tov Ve-Ha-Meitiv" over the $25 shirt while also having the 90 Million Dollar F-35 Stealth Fighter jet in mind… This reminds us of the story that when Ha-Rav Shlomo Goren was Chief Rabbi of Tel Aviv, he recited Shehechiyanu on the night of Yom Ha-Atzmaut in Shul as was his opinion. One of the people there questioned it, and Rav Goren waved his tie, as if to say that he was wearing a new tie, and so the blessing was on it. After the davening, Rav Goren scolded the man: It is obvious to you that one says Shehechiyanu on a new tie, but not on a new State?!