6分的话如果语法问题不大应该可以保证,这里只改语法,不说逻辑、句式和用词啦.
It is common for individuals fly to every corner of the world by airplanes.
individuals fly语意不清,to后面没有动词,fly和by airplanes重复.
改：It's common for individuals to fly to every corner of the world.
Even though some people insist that only richest people can benefit from air travel,I firmly that air travel benefit both richest people and ordinary people .
主句缺谓语（firmly不是动词）,benefit三单.
改：Even though some people insist that only richest people can benefit from air travel,I firmly believe that air travel benefits both richest people and ordinary people .
It is an undeniable fact that air travel costs more than car,train and ship.
more than car...有歧义（是air travel花的钱比买个car...还贵?还是air travel的钱比car...travel的钱贵?）.
改：It is an undeniable fact that travel by air costs more than travel by car,train or ship does.
However,airplanes have its unique superiority like fast and high-level service that other vehicles do not have.
airplanes和its不匹配,like一般不用在书面语中,fast and high-level service有歧义（是快速又高质量的服务?快速是修饰服务的?）.
改：However,airplanes have unique superiority that other vehicles do not have such as high speed,high-level service,and so forth.
Hence,some businessmen or millionaires prefer to take VIP flight and even their private airplane in order to have reduce the time spent in traveling.
to have reduce没有这种用法.
改：Hence,some businessmen or millionaires prefer to take VIP flight and even their private airplane in order to save time in traveling.
But it not mean that airplane is unavailable to other people.
but一般不在句首,it not mean错误.
改：Whereas it does not mean that airplane is unavailable to other people.
On the other hand,due to the development of modern airline business and some certain policy support,expenditure of air travel is no longer as high as before ,therefore,the number of air travelers that from the middle class is increasing continuously.
that 引导的定从不完整.
改：...of air travelers from the middle class is increasing continuously.
For instance,people can choose pay little more money than train tickets to sit in tourist class of the plane.
choose后面不能加动词原形.
改：For instance,people can choose to pay little more money than train tickets to sit in tourist class of the plane.
More discounts are available to travelers if they reserve airplane tickets in advance or they are students or armymen with relevant identifications.
with relevant identifications不了解你想表达的意思,你想说的是能提供相关证明的军人?
Furthermore,as the raising of living standard,people have enough disposable income to afford the expense of airplane which means that airplane offer benefits to the majority of people and become a universal vehicle for daily life.
as引导从句表示“随着……”的时候,后面应该是完整的句子；expense of airplane?买飞机的钱?；which不能指代整句；airplane 和offer、become主谓不一致；the majority的the错误.
改：Furthermore,as living standard rises,people have enough disposable income to afford the expense of air travel and,for this reason,airplane offers benefits to majority of people and becomes a universal vehicle for daily life.
To sum up,the era that air travel is for richest people have pasted away.
era和have主谓不一致.
改：To sum up,the era that air travel is for richest people has pasted away.
I feel that airplane is playing great role in common people’s travel because of socio-economic development.
没什么问题. 6分的话如果语法问题不大应该可以保证,这里只改语法,不说逻辑、句式和用词啦.
It is common for individuals fly to every corner of the world by airplanes.
individuals fly语意不清,to后面没有动词,fly和by airplanes重复.
改：It's common for individuals to fly to every corner of the world.
Even though some people insist that only richest people can benefit from air travel,I firmly that air travel benefit both richest people and ordinary people .
主句缺谓语（firmly不是动词）,benefit三单.
改：Even though some people insist that only richest people can benefit from air travel,I firmly believe that air travel benefits both richest people and ordinary people .
It is an undeniable fact that air travel costs more than car,train and ship.
more than car...有歧义（是air travel花的钱比买个car...还贵?还是air travel的钱比car...travel的钱贵?）.
改：It is an undeniable fact that travel by air costs more than travel by car,train or ship does.
However,airplanes have its unique superiority like fast and high-level service that other vehicles do not have.
airplanes和its不匹配,like一般不用在书面语中,fast and high-level service有歧义（是快速又高质量的服务?快速是修饰服务的?）.
改：However,airplanes have unique superiority that other vehicles do not have such as high speed,high-level service,and so forth.
Hence,some businessmen or millionaires prefer to take VIP flight and even their private airplane in order to have reduce the time spent in traveling.
to have reduce没有这种用法.
改：Hence,some businessmen or millionaires prefer to take VIP flight and even their private airplane in order to save time in traveling.
But it not mean that airplane is unavailable to other people.
but一般不在句首,it not mean错误.
改：Whereas it does not mean that airplane is unavailable to other people.
On the other hand,due to the development of modern airline business and some certain policy support,expenditure of air travel is no longer as high as before ,therefore,the number of air travelers that from the middle class is increasing continuously.
that 引导的定从不完整.
改：...of air travelers from the middle class is increasing continuously.
For instance,people can choose pay little more money than train tickets to sit in tourist class of the plane.
choose后面不能加动词原形.
改：For instance,people can choose to pay little more money than train tickets to sit in tourist class of the plane.
More discounts are available to travelers if they reserve airplane tickets in advance or they are students or armymen with relevant identifications.
with relevant identifications不了解你想表达的意思,你想说的是能提供相关证明的军人?
Furthermore,as the raising of living standard,people have enough disposable income to afford the expense of airplane which means that airplane offer benefits to the majority of people and become a universal vehicle for daily life.
as引导从句表示“随着……”的时候,后面应该是完整的句子；expense of airplane?买飞机的钱?；which不能指代整句；airplane 和offer、become主谓不一致；the majority的the错误.
改：Furthermore,as living standard rises,people have enough disposable income to afford the expense of air travel and,for this reason,airplane offers benefits to majority of people and becomes a universal vehicle for daily life.
To sum up,the era that air travel is for richest people have pasted away.
era和have主谓不一致.
改：To sum up,the era that air travel is for richest people has pasted away.
I feel that airplane is playing great role in common people’s travel because of socio-economic development.
没什么问题.