Setting boolean column based on cumulative integer value

Hi (again!)

[stupid email program sent my message before I finished it!!!]

I've got a bit of a tricky (for me!) problem. The example below is
completely ficticious but
describes my real problem in a way which might be easier to understand.

Imagine the table contains a list of passenger wanting to get on a
small(!) plane.
The plane can carry at most 200kg of passengers and will be filled
strictly on a first-come
first-serve basis - well, check-in staff is a bit stupid ;-). So what
needs to be done is to set the 'gets_seat' column to true until the
weight limit is reached.

CREATE TABLE passenger_queue (
id serial NOT NULL,
name character varying(40) NOT NULL,
weight integer NOT NULL,
gets_seat boolean default false
)

insert into passenger_queue values (1,"Peter",75,false)
insert into passenger_queue values (2,"Mary",50,false)
insert into passenger_queue values (3,"John",70,false)
insert into passenger_queue values (4,"Steve",80,false)

According to the specifications given above Peter, Mary and John would
have 'gets_seat'
set to true because their cumulative weight is 195kg while Steve misses out.

The big question is: How can I do this in a nice SQL query???

Thanks

Markus