Questions are to be asked in the comment section.
1) In years 1978 and 1979, there are very few passengers, why does this happen?
Answer: Passenger counts are determined by the world traveller index. They go up and down like in real life. Having very few passengers means that the world traveller index is either very low or your airline isn't getting enough passengers. This can be many reasons like satisfaction percentage being low or advertisements being ineffective. Check to see if satisfaction is low (in this case, renovate planes or offer more in flight services to customers) or raise advertisement spending to get more attention. Refer to question 6.
2) Why are Russian Airplanes are so fuel inefficient?
The Tu-204 is a fairly efficient airplane. In the game, it has an fuel efficiency of 5.9-6.3, which is not accurate at all. It should have ratings similar to a Boeing 757.
Also the speed of the airplanes need to be re-evaluated. For example, the 757 cruises much faster than at Mach 0.70, Mach 0.78-0.80 is much more accurate
Follow-up: In general, Tradegame depicts Russian aircraft as super cheap, but very fuel inefficient with low satisfaction. The fuel efficiency is very subjective, as what do they mean by 7.7 or 7.8? What does that unit mean? It is just a number to represent the efficiency compared to other aircraft. Generally speaking, the Russian planes in real life do have lower efficiency compared to the Western counterparts, but in the Tu-204's case I believe that Tradegame wanted go with the flow and just added poor efficiency. Tradegame tries to make the game as realistic as possible, but sometimes there can be a few minor errors.
3) I started my airline as an all-cargo airline and my fleet was composed entirely of Boeing 707-320Fs and I was making good profits and my value was skyrocketing, but then when the Boeing 747 was introduced, I replaced my 707 fleet entirely with B747-200Fs (about 70) and I continued only using the 747s for cargo. Gradually my value stopped growing, and my airline began to fail. But when I got rid of the 747s and replaced them with MD-11Fs, all of a sudden my value started going up again. What did the 747s have to do with my airline's decline, and what do I have to do to prevent this from happening again?
It seems that the 747s have higher maintenance expenses (which is shown as degraded value of your airplane, maybe?), so even though you gain some profits but it is not enough to cover up the losing value of the airplane (need some data though). So, the best way to utilized Boeing 747 perhaps longer the flight range means better the profits.
The 747 belongs on SOME, not all of your routes. The 747 is very pricey as it is a "gas guzzler". Remember, spare capacity doesn't make you any money. I would suggest experimenting with different aircraft to see which aircraft fit on which routes, however don't be careless about aircraft purchases. Also, operating a fleet of only one type of aircraft can be simpler and more cost effective, however the aircraft in question may not work for all your routes, so you may consider two types of aircraft.
747's have a very high depreciation cost. If routes are not earning 8.000-10,000k profit, then its not a good plane to use as it will have a negative effect on your value. Depreciation per month is calculated by the Current Value of a plane multiplied by 0.00399.
4) How do you know which channel goes to 2030 and which goes to 2020?
Answer: Channels in ATO starts in 1960 and ends in 2020.
Channels in ATO 2 starts from 1960 to 1970 and ends in 2020 AT 4 starts from 1960 and ends in 2030
5) How to you transfer your route to a different airport of the same city?
Answer: Yes you can, but first update your ATO2 to latest version. This feature only available for ATO2 only. First, Open the route management tab for your specified route. Providing you have slots in your airport of choice to change your flight to the blue button with the two control towers and switch arrows next to the departure/arrival city airport should be "lit up". Tap on the blue control tower switch icon and select your desired airport to switch to.
6) When does the economical crisis of 1979 start?
Answer: Economic crises will occur circa 1970-1980, 1990-2010, and 2010-2020. The crises will occur randomly during the periods stated above and so it is hard to predict when they may strike.
7) Can I buy or merge with other companies?
Answer: Yes you can, but this feature only available in Air Tycoon Online 2. You are required to pay the price of the company listed on the M&A Market (located under the invest tab) before being able to absorb the company.
8) How does the Fuel Tank work?
Answer: Fuel Tanks work by allowing you to purchase fuel at a discounted price (about 25% off market value) and storing it in the tanks. This helps lower expenses of your airline. The fuel will be used automatically according to the fuel requirement of your fleet and the airline may need to order additional fuel tanks as you expand your fleet. Fuel tanks cost credits (6 per tank in Air Tycoon Online 2) and have a monthly fee in order to keep it at that airport. In addition, the tanks can be built in any airport around the world and will be used to store fuel regardless of the location. Each fuel tank can hold up to 40Ml (Megalitres) of fuel.
In Air Tycoon Online 2, players have the option to sell fuel. There is a 2% commission fee required when you sell, so make sure you sell only when you are sure that you will profit from the sale. A useful tip to remember is to buy the fuel when the price is low and sell when the price is high.
Passenger routes tend to make more money, but they flucuate quite wildly. Cargo routes earn a lower income, but is more stable. Thats the pro and cons of both routes.
Passenger routes are often very competitive due to many players who start with passenger flights and the wider variety of passenger aircraft being available compared to cargo planes.
To increase profits for passenger routes, there are a few things that can be done. A good, but tedious, method is to adjust prices acoording to the peak periods and non peak periods. Peak months are on Jun to Sep and one more on Dec. While you can adjust prices by percentage with a tool in the route menu, it is best to do it individually as certain routes may require a bigger drop or rise compared tp others (e.g. between competition and monopoly). You can also raise service satisfaction to the max, this attracts more people and the added costs is minimal compared to the massive income that you can get from paying passengers.
For cargo routes, the best way to maximise profits is to avoid competition at all costs. Thankfully, this is not very hard to do as cargo operations are not wildly popular as passenger flights. If a competitor is present, use a high satisfaction aircraft or ensure prices are lower than his. The latter usually works very well as most people who put cargo don't really care too much on the condition of the plane. You can use Russian cargo planes and it can still beat western models as long as the price per ton is lower.
The best advice is to ALWAYS use fuel efficient planes. NEVER buy planes with a very low fuel efficiency (except Concorde or in the first 10 years of the game). Fuel is one of the biggest expenses for any airline, especially for airlines with no fuel tanks.
To beat competitors and make big money, use planes with high satisfaction, great examples that I love are the planes made by Airbus or Boeing as almost all of their planes comes with high satisfaction. McDonnell Douglas is only good for the first 20-30 years before they get absorbed by Boeing.